• 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

• Melanoma skin cancer

• Memory loss (amnesia)

• Ménière's disease

• Meningitis

• Meniscus tear (knee cartilage damage)

• Menopause

• Mesothelioma

• Metabolic syndrome

• Metallic taste

• Middle East respiratory syndrome (MERS)

• Migraine

• Miscarriage

• Mitral valve problems

• Molar pregnancy

• Moles

• Molluscum contagiosum

• Morton's neuroma

• Motion sickness

• Motor neurone disease

• Mouth cancer

• Mouth ulcers

• Mpox

• MRI scan

• MRSA

• Mucositis

• Multiple myeloma

• Multiple sclerosis

• Multiple system atrophy

• Mumps

• Muscular dystrophy

• Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS)

• Myasthenia gravis

• Myelodysplastic syndrome (myelodysplasia)

• Myositis