| Maize streak virus |
| Major Histocompatibility Complex |
| Malabsorption Syndromes |
| Malacoplakia |
| Malaria |
| Malaria Vaccines |
| Malaria, Avian |
| Malaria, Cerebral |
| Malaria, Falciparum |
| Malaria, Vivax |
| Malassezia |
| Malate Dehydrogenase |
| Malate Dehydrogenase (NADP+) |
| Malate Synthase |
| Malathion |
| Malawi |
| Malaysia |
| Maleic Anhydrides |
| Maleic Hydrazide |
| Mali |
| Malignant Carcinoid Syndrome |
| Malignant Catarrh |
| Malignant Hyperthermia |
| Malingering |
| Malleus |
| Mallophaga |
| Mallory-Weiss Syndrome |
| Mallotus Plant |
| Malnutrition |
| Malocclusion |
| Malocclusion, Angle Class I |
| Malocclusion, Angle Class II |
| Malocclusion, Angle Class III |
| Malonate-Semialdehyde Dehydrogenase (Acetylating) |
| Malondialdehyde |
| Malonyl Coenzyme A |
| Malpighiaceae |
| Malpighian Tubules |
| Malpractice |
| Malta |
| Maltose |
| Malus |
| Malva |
| Malvaceae |
| Mamillary Bodies |
| Mammals |
| Mammaplasty |
| Mammary Arteries |
| Mammary Glands, Animal |
| Mammary Glands, Human |
| Mammary Neoplasms, Animal |
| Mammary Neoplasms, Experimental |
| Mammary Tumor Virus, Mouse |
| Mammea |
| Mammography |
| Man-Machine Systems |
| Managed Care Programs |
| Managed Competition |
| Management Audit |
| Management Information Systems |
| Management Quality Circles |
| Management Service Organizations |
| Mandatory Programs |
| Mandatory Reporting |
| Mandatory Testing |
| Mandelic Acids |
| Mandible |
| Mandibular Advancement |
| Mandibular Condyle |
| Mandibular Fractures |
| Mandibular Injuries |
| Mandibular Neoplasms |
| Mandibular Nerve |
| Mandibular Prosthesis |
| Mandibular Prosthesis Implantation |
| Mandibulofacial Dysostosis |
| Mandragora |
| Mandrillus |
| Manduca |
| Maneb |
| Manganese |
| Manganese Compounds |
| Manganese Poisoning |
| Mangifera |
| Manifest Anxiety Scale |
| Manihot |
| Manilkara |
| Manipulation, Chiropractic |
| Manipulation, Orthopedic |
| Manipulation, Osteopathic |