| M. leprae | Mycobacterium leprae |
|---|---|
| M. tuberculosis | Mycobacterium tuberculosis |
| M.A.O. | Maximal Acid Output |
| M.C.T.D. | Mixed Connective Tissue Disease |
| M.D.D. | Major Depressive Disorder |
| M.D.I. | Metered Dose Inhaler |
| M.E.C. | minimal effective concentration |
| M.E.D. | Multiple epiphyseal dysplasia |
| M.E.M. | Minimum Essential Medium |
| m.e.p.c. | Miniature end-plate current |