M
- Malformation, Ebstein's - child
- Malignant fibrous histiocytoma
- Malignant peripheral nerve sheath tumor
- Mask of pregnancy
- MD
- Melasma
- Mental retardation
- Metatarsalphalangeal joint sprain
- Methicillin-resistant Staphylococcus aureus
- Macrocytic achylic anemia
- Macrosomia
- Macular degeneration
- Malabsorption
- Malaria
- Male erectile disorder
- Male infertility
- Malignant astrocytoma
- Malignant hepatoma
- Malignant hypertension
- Malingering
- Mallet finger
- Malta fever
- Mammary dysplasia
- Mandible fracture
- Manic-depressive illness
- Manic affective disorder
- Manic disorder
- March stress fracture
- Marfan syndrome
- Marie-Strumpell disease
- Martin-Bell syndrome
- Mastalgia
- Mastitis
- Maxillary fracture
- MDS
- Measles
- Mechanical bowel obstruction
- Meckel's diverticulum
- Medial apophysitis
- Medial distal tibial syndrome, MDTS
- Medial epicondylitis
- Medial tibial stress syndrome
- Medial tibial syndrome
- Melanoma
- Meniere's disease
- Meningioma
- Meningitis
- Meniscal tear
- Menkes syndrome
- Menopause
- Menorrhagia
- Menstrual cramps
- Mercury toxicity
- Mesothelioma, pleura
- Metabolic syndrome
- Metatarsalgia
- MG
- Middle ear infection
- Migraine headache (adult)
- Migraine - child
- Mild cognitive impairment
- Mild traumatic brain injury
- Mini-stroke
- Miscarriage
- Mitochondrial DNA depletion syndrome
- Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes
- Mitochondrial myopathy
- Mitochondrial neurogastrointestinal encephalopathy
- Mitral insufficiency
- Mitral regurgitation
- Mitral stenosis - adult
- Mitral stenosis - child
- Mitral valve prolapse
- Mitral valve stenosis - adult
- Mitral valve stenosis - child
- Mittelschmertz
- Mixed apnea
- Moles
- Molluscum contagiosum
- Monilial vulvovaginitis
- Mononucleosis
- Montezuma’s revenge
- Mood disorders
- Morbid obesity in adults
- Morton's neuroma
- Mosquito-borne viral encephalitis
- Motion sickness
- Motor neuron disease
- Movement disorder
- MRSA
- MS - adult
- MS - child
- MSA
- MTSS
- Mucocutaneous lymph node syndrome
- Mucormycosis
- Mucosal prolapse
- Mucous colitis
- Mud fever
- Multi-system atrophy
- Multi-system degeneration
- Multiple myeloma
- Multiple sclerosis - adult
- Multiple sclerosis - child
- Multiple system atrophy
- Multiple system atrophy with postural hypotension
- Multiply-Resistant Enterococci
- Mumps
- Munchausen syndrome
- Muscle contraction headache
- Muscle cramps
- Muscle strain, forearm
- Muscle strain
- Muscular dystrophy
- Mutilating hand injuries
- MVP
- Mya's disease
- Myasthenia gravis
- Myelodysplasia
- Myelodysplastic syndrome
- Myelopathy, cervical
- Myocardial infarction
- Myocarditis - child
- Myocarditis—adult
- Myoclonic epilepsy associated with ragged red fibers
- Myoclonus
- Myoma
- Myopia and hyperopia