- Maalox, for esophageal diverticula
- MACOP-B, for non-Hodgkin lymphoma
- Macrolide antibiotics
- Mafenide acetate, for burns
- Magnesium
- Magnesium gluconate (Almora), for hypomagnesemia
- Magnesium salts, for gastroesophageal reflux disease
- Magnesium sulfate
- Magnetic resonance imaging (MRI)
- Major Types of Primary Bone Cancer
- Malignant hypertension
- Malignant lymphoma
- Malignant plasmacytoma
- Mallory-Weiss syndrome
- Malnutrition
- Mammogram
- Mannitol
- Manometry, esophageal
- Mastectomy, for breast cancer
- Mastitis
- Mean corpuscular volume (MCV), in iron deficiency anemia
- Mechanical ventilation
- Medical expulsive therapy (MET), for renal calculi
- Medications, anaphylaxis from
- Medroxyprogesterone acetate (Provera)
- Megaloblasts
- Meglitinide derivatives, for diabetes mellitus
- Melanoma skin cancer
- Melphalan
- Memory loss, in Alzheimer disease
- Meningitis
- Meperidine (Demerol)
- 6-Mercaptopurine, for Crohn disease
- Meropenem (Merem)
- Mesalamine (5-aminosalicylic acid; 5-ASA)
- Metabolic acidosis
- Metabolic alkalosis
- Metanephrine
- Metaprolol, for pheochromocytoma
- Metaproterenol, for emphysema
- Methazolamide, for glaucoma
- Methergine, for spontaneous abortion
- Methimazole (Tapazole), for hyperthyroidism
- Methotrexate
- Methotrexate sodium (Folex), for ectopic pregnancy
- Methyl-1-(2-Chloroethyl)-3-Cyclohexyl-1-Nitrosourea (CCNU), for gastric cancer
- Methyldopa (Aldomet)
- Methylergonovine (Methergine), for postpartum hemorrhage
- Methylprednisolone (Solu-Medrol)
- Methylprednisolone IV
- Metoclopramide, for gastroesophageal reflux disease
- Metolazone (Zaroxalyn), for heart failure
- Metoprolol
- Metronidazole (Flagyl)
- Mezlocillin, for chorioamnionitis
- Micafungin, for candidiasis
- Miconazole, for candidiasis
- Miconazole nitrate, for vaginitis
- Microdiscectomy, for herniated disk
- Midazolam (Versed)
- Middle ear effusion (MEE)
- Migraine headache
- Mild traumatic brain injury (MTBI)
- Mill-wheel murmur, in air embolism
- Milrinone, for myocardial contusion
- Mineralocorticoids, for adrenal insufficiency
- Minnesota tube, for Mallory-Weiss syndrome
- Minocycline, for rheumatoid arthritis
- Minoxidil, for heart failure
- Miotic eyedrops, for glaucoma
- Misoprostol
- Mitoguazone, for esophageal cancer
- Mitomycin
- Mitotane, for Cushing syndrome
- Mitoxantrone, for chronic leukemia
- Mitral insufficiency (regurgitation)
- Mitral stenosis
- Mitral valve prolapse (MVP)
- Mivacurium (Mivacron)
- Mohs micrographic surgery, for skin cancer
- Mometasone, for asthma
- Moniliasis
- Monitoring, for infant at risk for SIDS
- Monoamine oxidase B (MOA-B) inhibitors, for Parkinson disease
- Monoclonal antibodies
- Monocytes
- Mononucleosis, infectious
- Monospot, in infectious mononucleosis
- Montelukast, for asthma
- Morphine
- Motor vehicle crashes (MVCs)
- Mucolytic, for cystic fibrosis
- Multigated blood pool imaging, in heart failure
- Multiple myeloma
- Multiple organ dysfunction syndrome (MODS)
- Multiple sclerosis
- Multiple subpial transection (MST), for epilepsy
- Multivitamin supplements
- Murmur
- Muscle(s)
- Muscle relaxants
- Muscular dystrophy
- Musculoskeletal system
- Musculoskeletal Trauma
- Mustargen, for Hodgkin disease
- M-VAC, for bladder cancer
- Myasthenia gravis
- Mycophenolate, for lupus erythematosus
- Myelogenous leukemia
- Myeloma, multiple
- Myelomatosis
- Mylanta, for esophageal diverticula
- Myocardial (cardiac) contusion
- Myocardial Infarction
- Myocardial infarction (MI)
- Myocarditis
- Myoglobin, urine, in musculoskeletal trauma
- Myotomy, cricopharyngeal, for esophageal diverticula
- Myotonic dystrophy