M
- Macular hole
- Magnesium test
- Malaria
- Malignant brain tumour (brain cancer)
- Mallet finger
- Malnutrition
- Maple syrup urine disease
- Marfan syndrome
- Mastectomy
- Mastitis
- Mastocytosis
- Mastoiditis
- MCADD
- Measles
- Medical cannabis (and cannabis oils)
- Medically unexplained symptoms
- Medicines information
- Memory loss (amnesia)
- Ménière's disease
- Meningitis
- Menopause
- Mental health and wellbeing
- Mesothelioma
- Metabolic syndrome
- Metallic taste
- Middle East respiratory syndrome (MERS)
- Migraine
- Miscarriage
- Mitral valve problems
- Molar pregnancy
- Moles
- Molluscum contagiosum
- Monkeypox
- Morton's neuroma
- Motion sickness
- Motor neurone disease
- Mouth cancer
- Mouth ulcers
- MRI scan
- MRSA
- Mucositis
- Multiple myeloma
- Multiple sclerosis
- Multiple system atrophy
- Mumps
- Munchausen's syndrome
- Muscular dystrophy
- Myasthenia gravis
- Mycobacterium chimaera infection
- Myelodysplastic syndrome (myelodysplasia)
- Myositis (polymyositis and dermatomyositis)
