| JPhPh | Journal of Pharmacy and Pharmacology | In English | → Serial publications, periodicals → Pharmacology, toxicology |
| JPhsg | Journal of Physiology | In English | → Serial publications, periodicals → Physiology |
| JPS | Journal of Pharmacological Sciences | In English | → Serial publications, periodicals → Pharmacology, toxicology |
| JRCSE | Journal of the Royal College of Surgeons of Edinburgh | In English | → Serial publications, periodicals → Surgery, orthopaedics, ophthalmology |
| JSOG | Japanese Society of Obstetrics and Gynecology | In English | → Organizations and associations → Gynaecology → Obstetrics |
| KAV | Krankenanstaltenverbund | In German | → Public health and hygiene |
| KKS | Koordinierungszentrum für Klinische Studien | In German | → Veterinary medicine |
| KNDB | Koninklijke Nederlandse Drogisten Bond | In Dutch | → Organizations and associations → Pharmacology, toxicology |
| LA | Leucémie Aiguë | In French | → Blood and circulatory system → Pathology |
| LAB | Laboratoire d'Accidentologie et de Biomécanique | In French | → Research institutes → Traumatology → Transport and postal services |
| LAL | Leucémie Aiguë Lymphoïde | In French | → Blood and circulatory system → Pathology |
| LAM | Leucémie Aiguë à Mégacaryocytes | In French | → Blood and circulatory system → Pathology |
| LAM | Leucémie Aiguë Myéloïde | In French | → Blood and circulatory system → Pathology |
| LASS | Laboratoire d'Analyse des Systèmes de Santé | In French | → Research institutes → Public health and hygiene |
| LAUF | Landssamtök áhugafólks um flogaveiki (www.lauf.is) | In Icelandic | → Organizations and associations → Neurology |
| LBE | Liga Brasileira de Epilepsia | In Portuguese | → Organizations and associations → Neurology |
| LBICR | Ludwig Boltzmann Institut for Cancer Research | In English | → Oncology |
| LCA | Leber's Congenital Amaurosis | In English | → Pathology |
| LCE | Liga Colombiana contra la Epilepsia | In Spanish | → Organizations and associations → Neurology |
| LCI | Laboratory of Clinical Investigation | In English | → Research institutes |
| LCS | Libyan Cardiac Society | In English | → Organizations and associations → Cardiology |
| LDF | Ligue des Diabétiques de France (www.diabetenet.com) | In French | → Organizations and associations → Physiology → Pathology |
| LEAD | Lupus Érythémateux Aigu Disséminé | In French | → Immunology and allergy → Pathology |
| LED | Lupus Érythémateux Disséminé | In French | → Pathology |
| LEE | Locus of Enterocyte Effacement | In English | → Blood and circulatory system → Pathology |
| LEEM | Les Entreprises du Médicament | In French | → Pharmacology, toxicology |
| LES | Lupus Érythémateux Systémique = SLE | Systemic Lupus Erythematosus | In English |
In French | → Immunology and allergy → Pathology |
| LETS | Leiden Thrombophilia Study | In English | → Pharmacology, toxicology → Pathology |
| LFB | Laboratoire français du Fractionnement et des Biotechnologies (www.lfb.fr) | In French | → Biotechnology → Pharmacology, toxicology |
| LFCE | Ligue Française Contre l'Épilepsie (www.lfce-epilepsies.fr) | In French | → Organizations and associations → Neurology |
| LH | Luteinizing Hormone | In English | → Hormones → Gynaecology |
| LH | Lateral Hypodermis | In English | |
| LICE | Lega Italiana Contro L'Epilessia (www.lice.it) | In Italian | → Organizations and associations → Neurology |
| LICHE | Liga Chilena contra la Epilepsia (www.ligaepilepsia.cl) | In Spanish | → Organizations and associations → Neurology |
| LIEF | Ligue des Infirmiers et des Infirmières de l'Espace Francophone | In French | → Organizations and associations |
| LISA | Life Science Austria | In English | → Biological sciences |
| LMC | Leucémie Myéloïde Chronique | In French | → Blood and circulatory system → Pathology |
| LMM | Laboratory of Metabolic Medicine | In English | → Research institutes → Physiology |
| LMP | Last Menstrual Period | In English | → Gynaecology |
| LMPV | Leucomalacie périventriculaire = PVL | Periventrikuläre Leukomalazie | In German = PVL | Periventricular Leukomalacia | In English = PVL | Periventriculaire Leukomalacie | In Dutch |
In French | → Obstetrics → Neurology |
| LMSS | Liverpool Medical Students Society | In English | → Organizations and associations → Higher education, universities |
| LNCC | Ligue Nationale Contre le Cancer | In French | → Organizations and associations → Oncology |
| LP | Luteal Phase | In English | → Gynaecology |
| LPD | Luteal Phase Defect | In English | → Gynaecology → Reproductive biology |
| LPPA | Laboratoire de la Physiologie, de la Perception et de l'Action | In French | → Research institutes → Physiology |
| LPPE | Laboratoire de Physiologie et de Psychologie Expérimentales | In French | → Research institutes → Psychology → Physiology |
| LRPAT | Laboratoire de Recherche en Pathologies Radio-induites | In French | → Research institutes → Pathology |
| LSE | Life Support Equipment | In English | |
| LSO | Life Systems Officer | In English | |
| LSS | Life Support System | In English | |
| LSU | Life Support Umbilical | In English | |
| LUMC | Leiden University Medical Center (www.lumc.nl) | In English | → Higher education, universities |
| LUSSI | Laboratoire UltraSons, Signaux et Instrumentation (www.lussi.univ-tours.fr) | In French | → Research institutes → Diagnostics |
| LUV | Large Unilamellar Vesicle | In English | → Biotechnology → Pharmacology, toxicology |
| LVH | Left Ventricular Hypertrophy | In English | → Cardiology |
| LVRS | Lung Volume Reduction Surgery | In English | → Chest diseases |
| M/C | Miscarriage | In English | → Obstetrics → Reproductive biology |
| MAA | Marketing Authorization Application | In English | → Pharmacology, toxicology |
| MAEH | Mouvement pour l'Amélioration de l'Environnement Hospitalier | In French | → Organizations and associations |
| MAN | Médecine d'Afrique Noire | In French | → Serial publications, periodicals |
| MAP | Multiple Antigenic Peptide | In English | → Biochemistry, biophysics → Immunology and allergy |
| MARC | Multiple Artificial Retina Chipset | In English | → Electronics |
| MAS | Morbus Alzheimer Syndrom | In German | → Neurology |
| MAT | Microangiopathie thrombotique | In French | → Blood and circulatory system → Pathology |
| MAV | Malformation artérioveineuse | In French | → Pathology |
| MBC | Maximum Breathing Capacity | In English | → Anatomy |
| MBK | Medications and Bandage Kit | In English | |
| MCBO | Molecular Cell Biology and Oncology Graduate Program | In English | → Education → Cytology → Oncology |
| MCH | Mean Corpuscular Haemoglobin = HCM | Hémoglobine Corpusculaire Moyenne | In French |
In English | → Blood and circulatory system |
| MCH | Medisch Centrum Haaglanden | In Dutch | |
| MCHC | Metropolitan Chicago Healthcare Council | In English | → Organizations and associations |
| MCHC | Mean Corpuscular Hemoglobin Concentration = CCMH | Concentration Corpusculaire Moyenne en Hémoglobine | In French |
In English | → Blood and circulatory system |
| MCHC | Minnesota Chinese Health Center | In English | |
| MCHC | Mean Cell Hemoglobin Concentration | In English | → Blood and circulatory system |
| MCHC | Family Health Bureau | In English | |
| MCHC | Maternal and Child Health Coalition | In English | → Organizations and associations → Gynaecology → Pediatry |
| MCI | Mild Cognitive Impairment | In English | → Neurology |
| MCJ | Maladie de Creutzfeldt-Jakob | In French | → Neurology |
| MCNV | Medisch Comité Nederland-Vietnam | In Dutch | → Organizations and associations |
| MCP | Monocyte Chemoattractant Protein | In English | → Biochemistry, biophysics → Immunology and allergy |
| MCV | Mean Corpuscular Volume = VGM | Volume Globulaire Moyen | In French |
In English | → Blood and circulatory system |
| MDCK | Madin–Darby Canine Kidney | In English | → Biological sciences → Anatomy |
| MDM | Médecins du Monde | In French | → Organizations and associations |
| MDS | Médicament Dérivé du Sang ou du plasma humain | In French | → Pharmacology, toxicology |
| MEDICS | Medical Information Computer System | In English | → Computer science |
| MEEI | Massachusetts Eye and Ear Infirmary | In English | → Surgery, orthopaedics, ophthalmology → Ophtalmology |
| MEG | Magnetoencephalography | In English | → Neurology |
| MEG | MagnétoEncéphaloGraphe | In French | |
| MeSH | Medical Subject Headings | In English | → Bibliography → Libraries |
| MGH | Massachusetts General Hospital | In English | |
| MH | Medical History | In English | → History |
| MHLA | Maritimes Health Libraries Association = ABSM | Association des Bibliothèques de la Santé des Maritimes | In French |
In English | → Libraries → Associations → 6295 |
| MHRA | Medicines and Healcare products Regulatory Agency | In French | → Public administration, government → Public health and hygiene |
| MIDD | Maternally Inherited Diabetes and Deafness | In English | → Pathology |
| MIMS | Medical Information Management System | In English | → Management |
| MIV | Menslike Immuniteitsgebreksvirus = VIH | Virus de l'Immunodéficience Humaine | In French = HIV | Human Immunodeficiency Virus | In English = VIH | Virus d'Inmunodeficencia Humana | In Asturian = VIH | Vírus da imunodeficiência humana | In Portuguese = VIDH | Virus Immunitarii Defectus Humanae | In Latin = ŽIV | Žmogaus Imunodeficito Virusas | In Lithuanian = ХИВ | Хумане имунодефицијенције | In Serbian = HIV | Humani Imunodeficientni Virus | In Slovenian = ВИЧ | Вирус иммунодефицита человека | In Russian = GIB | Giza Immunoeskasiaren Birusa | In Basque |
In Afrikaans | → Virology → Immunology and allergy → Infectious diseases |
| MMI | Medicus Mundi Italia | In Italian | → Organizations and associations |
| MMM | Myélofibrose avec Métaplasie Myéloïde | In French | → Blood and circulatory system → Pathology |
| MMS | Medical Mission Sisters | In English | → Roman catholic church |
| MMSE | Mini-Mental State Examination | In English | |
| MMT | Médecins Maîtres-Toile | In French | → Networks, communication → Organizations and associations |
| MMTV | Mouse Mammary Tumor Virus | In English | → Virology → Oncology |
| MMW | Münchener Medizinische Wochenschrift | In German | → Serial publications, periodicals |
| MoBiMed | Molekulare Bildgebung in der Medizin | In German | → Biological sciences |
| MODY | Maturity-Onset Diabetes of the Young | In English | → Pathology |
| MOE | Munduko Osasun Erakundea = MOS | Monda Organiz(aĵ)o pri Sano | In Esperanto = WHO | World Health Organization | In English = OMS | Organisation Mondiale de la Santé | In Esperanto = OMS | Organizzazione Mondiale della Sanità | In Italian = WGO | Wêreldgesondheidsorganisasie | In Afrikaans = OMS | Organización Mundial de la Salú | In Asturian = СЗО | Световната здравна огранизация | In Bulgarian = SZO | Světová zdravotnická organizace | In Czech = OMS | Organització Mundial de la Salut | In Catalan = OMS | Organización Mundial de la Salud | In Spanish = MTO | Maailma Terviseorganisatsioon | In Estonian = OMS | Organisacion mondiâla de la sandât | FRP = OMS | Organización Mundial da Saúde | In Galician = SZO | Svjetska zdravstvena organizacija | In Croatian = RTD | Rêxistina Tendurustiyê ya Dinyayê | In Kurdish = UMS | Urganizazziun mundiala da la Santaa | In Lombard = PSO | Pasaulio sveikatos organizacija | In Lithuanian = PVO | Pasaules veselības organizācija | In Latvian |
In Basque | → United Nations |
| MORD | Medical Operations Requirements Document | In English | |
| MOS | Monda Organiz(aĵ)o pri Sano = MOE, WHO, OMS, WGO, СЗО, SZO, MTO, RTD, UMS, PSO, PVO (look above) |
In Esperanto | → United Nations |
| MPGN | Membranoproliferative Glomerulonephritis | In English | → Pathology |
| MPH | Master of Public Health | In French | → Higher education, universities → Public health and hygiene |
| MPOC | Maladie Pulmonaire Obstructive Chronique | In French | → Pathology |
| MR | Magnetska ili magnetna rezonancija | In Croatian | → Nuclear, atomic, and molecular physics |
| MRC | Medical Research Council | In English | → Organizations and associations |
| MRD | Minimal Residual Disease | In English | → Pathology |
| MRI | Magnetic Resonance Imagery = IRM | Imagerie par Résonance Magnétique | In French |
In English | → Nuclear, atomic, and molecular physics |
| MRT | Magnetresonanstomografi = MRT | Magnetresonanz-Tomografie | In German |
In Swedish | → Nuclear, atomic, and molecular physics |
| MRT | Magnetresonanz-Tomografie = (look above) |
In German | → Nuclear, atomic, and molecular physics |
| MRZ | Medizinisches Rechenzentrum | In German | → Computer science |
| MS | Multiple Sclerosis | In English | → Neurology |
| MS | Ministerul Sănătăţii | In Romanian | → Central administration → Public health and hygiene |
| MSBCIA | Macedonian Society for Basic, Clinical Immunology and Allergology | In English | → Organizations and associations → Immunology and allergy |
| MSBM | Maîtrise de Sciences Biologiques et Médicales | In French | → Higher education, universities → Biological sciences |
| MSE | Medical Support Equipment | In English | |
| MSF | Médecins Sans Frontières | In French | → Organizations and associations |
| MSHA | Mine Safety and Health Administration | In English | |
| MSJ | Medical Sisters of Saint Joseph | In English | → Roman catholic church |
| MTEV | Maladie Thromboembolique Veineuse | In French | → Blood and circulatory system |
| MTO | Maailma Terviseorganisatsioon = MOE, MOS, WHO, OMS, WGO, СЗО, SZO, RTD, UMS, PSO, PVO (look above) |
In Estonian | → United Nations |
| MUG | Medizinische Universität Graz | In German | → Higher education, universities |
| MUMPS | Massachusetts General Hospital Utility Multi-Programming System | In English | → Programming languages |
| MUSE | Medicated Urethral System for Erection | In English | → 3926 → Urology |
| MUW | Medizinische Universität Wien | In German | → Higher education, universities |
| MVL | Multilamellar Vesicle | In English | → Biotechnology → Pharmacology, toxicology |
| MVO | Maladie Veino-Occlusive | In French | → Pathology |
| MW | Medische Wetenschappen | In Dutch | |
| NACCP | National Association of Child Care Professionals | In English | → Associations → Pediatry |
| NAN | Nombre Absolu de Neutrophiles | In French | → Blood and circulatory system |
| NASH | Nicht-alkoholische Steatohepatitis | In German | → Pathology |
| NASS | North American Spine Society | In English | → Organizations and associations |
| NCA | National Care Association (www.nca.gb.com) | In English | → Associations → Social welfare |
| NCI | National Cancer Institute | In English | → Oncology |
| NCM | Neural Control of Movement Society (http://ncm-society.org) | In English | → Organizations and associations → Neurology |
| NDA | New Drug Application | In English | → Pharmacology, toxicology |
| NDL | National Diet Library | In English | → Libraries → Nutrition |
| NEJM | New England Journal of Medicine | In English | → Serial publications, periodicals |
| NEOBRAIN | Neonatal Estimation Of Brain Damage Risk And Identification of Neuroprotectants | In English | → Neurology → Obstetrics |
| NETT | National Emphysema Treatment Trial | In English | → Chest diseases |
| NGF | Nerve Growth Factor | In English | → Hormones → Neurology" |
| NHF | National Hemophilia Foundation | In English | → Foundations → Blood and circulatory system → Pathology |
| NHLBI | National Heart, Lung, and Blood Institute (www.nhlbi.nih.gov) | In English | → Research institutes → Blood and circulatory system → Cardiology |
| NICE | National Institute for Health and Clinical Excellence | In English | |
| NIDDK | National Institute of Diabetes and Digestive and Kidney Diseases | In English | → Research institutes → Physiology → Pathology |
| NIFTE | National Initiative for Telehealth | In English | |
| NIH | National Institutes of Health (www.nih.gov) | In English | → Research institutes → Biological sciences |
| NIMH | National Institute of Mental Health | In English | → Neurology |
| NIOSH | National Institute for Occupationnal Safety and Health | In English | → Labour, labour economics |
| NIOSH | National Institute for Occupational Safety and Health | In English | → Labour, labour economics |
| NIPS | National Institute for Physiological Sciences | In English | → Research institutes → Physiology |
| NKI-AVL | Nederlands Kanker Instituut - Antoni van Leeuwenhoek Ziekenhuis | In Dutch | → Oncology |
| NMC | Nursing and Midwifery Council | In English | → Organizations and associations |
| NMI | Naturwissenchaftlich-Medizinisches Institut | In English | → Biological sciences |
| NMMBC | Neuropathie Motrice Multifocale à Bloc de Conduction | In French | → Neurology |
| NMR | Nuclear Magnetic Resonance = RMN | Résonance Magnétique Nucléaire | In French = RMN | Ressonància Magnètica Nuclear | In Catalan = RMN | Risonanza Magnetica Nucleare | In Italian = תמ"ג | תהודה מגנטית גרעינית | In Hebrew = ЯМР | Я́дерного магни́тного резона́нса | In Russian = НМР | Нуклеарна магнетна резонанција | In Serbian |
In English | → Nuclear, atomic, and molecular physics → 629031 |
| NN | Neural Networks | In English | → Serial publications, periodicals → Computer-based techniques → Neurology |
| NPH | Neutral Protamine Hagedorn | In English | → Cardiology |
| NRK | Nederlandse Rode Kruis | In Dutch | → Organizations and associations |
| NSLC | Non-Small cell Lung Carcinoma | In English | → Chest diseases → Oncology |
| NTA | National Treatment Agency for Substance Misuse | In English | → Personal health and hygiene |
| nvMCJ | Nouveau variant de la Maladie de Creutzfeldt-Jakob | In French | → Neurology |
| NVTG | Nederlandse Vereniging voor Tropische Geneeskunde | In Dutch | → Organizations and associations |
| ÖÄGM | Österreichische Ärztegesellschaft für Manuelle Medizin | In German | → Organizations and associations |
| ÖÄK | Österreichische Ärztekammer | In German | |
| OASM | Office of Aerospace Medicine | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OBS | Operational Biomedical System | In English | |
| OBS | Operational Bioinstrumentation System | In English | |
| OBVP | Österreichischer Bundesverband für Psychotherapie (www.psychotherapie.at) | In German | → Organizations and associations → Psychology → Neurology |
| OCD | Obsessive Compulsive Disorder | In English | → Psychology → Neurology |
| ÖDG | Österreichische Diabetes-Gesellschaft | In German | → Organizations and associations → Pathology |
| OEC | Olfactory Ensheathing Cell | In English | → Anatomy |
| OECI | Organisation of European Cancer Institutes | In English | → Organizations and associations → Oncology |
| OECI | Organization of European Cancer Institutes (www.oeci-eeig.org) | In English | → Organizations and associations → Research institutes → Oncology |
| OEGGG | Österreichische Gesellschaft für Gynäkologie und Geburtshilfe (www.oeggg.at) | In German | → Organizations and associations → Gynaecology → Obstetrics |
| ÖGA | Österreichische Gesellschaft für Akupunktur | In German | |
| ÖGAI | Österreichische Gesellschaft für Allergologie und Immunologie | In German | → Organizations and associations → Immunology and allergy |
| ÖGAM | Österreichische Gesellschaft für Allgemeinmedizin | In German | → Organizations and associations |
| ÖGARI | Österreichische Gesellschaft für Anaesthesiologie, Reanimation und Intensivmedizin | In German | → Organizations and associations → Traumatology → Anesthesiology |
| ÖGDV | Österreichische Gesellschaft für Dermatologie und Venerologie | In German | → Organizations and associations → Dermatology |
| ÖGGG | Österreichische Gesellschaft für Geriatrie und Gerontologie | In German | → Organizations and associations → Gerontology |
| ÖGGH | Österreichische Gesellschaft für Gastroenterologie und Hepatologie | In German | → Organizations and associations → Pathology |
| ÖGHO | Österreichische Gesellschaft für Hämatologie und Onkologie | In German | → Organizations and associations → Oncology |
| ÖGIM | Österreichische Gesellschaft für Innere Medizin | In German | → Organizations and associations |
| ÖGK | Österreichisches Grünes Kreuz (www.gruenes-kreuz.org) | In German | → Organizations and associations |
| OGKA | Österreichische Gesellschaft für kontrollierte Akupunktur | In German | → Organizations and associations |
| ÖGKC | Österreichische Gesellschaft für klinische Chemie | In German | → Organizations and associations → Biochemistry, biophysics → Pharmacology, toxicology |
| ÖGKJ | Österreichische Gesellschaft für Kinder- und Jugendheilkunde (www.docs4you.at) | In German | → Organizations and associations → Pediatry |
| ÖGLUT | Österreichische Gesellschaft für Lungenerkrankungen und Tuberkulose | In German | → Organizations and associations → Chest diseases → Infectious diseases |
| ÖGN | Österreichische Gesellschaft für Nuklearmedizin | In German | → Organizations and associations |
| ÖGN | Österreichische Gesellschaft für Neurologie | In German | → Organizations and associations → Neurology |
| ÖGP | Österreichische Gesellschaft für Pneumologie | In German | → Organizations and associations → Chest diseases |
| ÖGPB | Österreichische Gesellschaft für Neuropsychopharmakologie und Biologische Psychiatrie | In German | → Organizations and associations → Pharmacology, toxicology → Neurology → Psychiatry |