| MES Hydrate | | Other calcium Channel Blockers | 1 |
| MES Sodium | | Other calcium Channel Blockers | 1 |
| Mecasermin | 68562-41-4 | Somatropin Agonists | 1 |
| Mechlorethamine | 51-75-2 | Alkylating agents | 1 |
| Medetomidine hydrochloride | 86347-15-1 | | 1 |
| Meglumine | 6284-40-8 | Contrast Media | 1 |
| Meldonium | 86426-17-7 | | 1 |
| Meldrum's Acid | 2033-24-1 | | 1 |
| Melengestrol Acetate | 2919-66-6 | Progestagens | 1 |
| Melitracen Hydrochloride | 10563-70-9 | | 1 |
| Melperone | 3575-80-2 | | 1 |
| Melphalan hydrochloride | 3223-07-2 | | 1 |
| Menadione Sodium Bisulphite | 6147-37-1 | Vitamins | 1 |
| Menbutone | 74381-53-6 | | 1 |
| Menotropins | 61489-71-2 | Gonadotrophic | 1 |
| Mentha pulegium | | Herbal remedies | 1 |
| Menthae piperitae folium | | Herbal remedies | 1 |
| Menthae viridis folium | | Herbal remedies | 1 |
| Mepenzolate | 25990-43-6 | Anticholinergics/Parasympathemimetics | 1 |
| Mepolizumab | 196078-29-2 | Anti-asthma | 1 |
| Mertansine | 139504-50-0 | Oncolytics | 1 |
| Mesterolone | 1424-00-6 | Androgens | 1 |
| Metallic Silver Powder | 7440-22-4 | Antimicrobial agents | 1 |
| Methacycline | 914-00-1 | Tetracyclines | 1 |
| Methamphetamine | 537-46-2 | Psychostimulants | 1 |
| Methanesulfonic Anhydride | 7143-01-3 | | 1 |
| Methohexital | 151-83-7 | Intravenous anesthetics | 1 |
| Methopabate | 4093-29-2 | | 1 |
| Methsuximide | 77-41-8 | Adrenergic agents | 1 |
| Methyclothiazide | 135-07-9 | Diuretics | 1 |
| Methyl (3aR,4R,6S,6aS)-4-((tert-butoxycarbonyl)amino)-3-(pentan-3-yl)-3a,5,6,6a-tetrahydro-4H-cyclopenta[d]isoxazole-6-carboxyla | 229613-93-8 | | 1 |
| Methyl 2 Oxo-2,3 Dihydro-1H-Pyrrolo[2,3-B] Pyridine-6-Carboxylate | 1227268-70-3 | Intermediates | 1 |
| Methyl 2-(4-(2-Chloroethyl) Phenyl) -2-Methylpropanoate | 1181267-33-3 | Intermediates | 1 |
| Methyl 2-(4-(4-(4-(hydroxydiphenylmethyl)piperidin-1-yl)butanoyl)phenyl)-2-methylpropanoate | 154477-55-1 | Intermediates | 1 |
| Methyl 2-Hydroxy-3-Nitrobenzoate | 22621-41-6 | Intermediates | 1 |
| Methyl 3-Hydroxy-4-Methoxybenzoate | 6702-50-7 | Intermediates | 1 |
| Methyl 4-Chlorocinnamate | 7560-44-3 | Dermatics | 1 |
| Methyl 5-Hydroxypentanoate | 14273-92-8 | Intermediates | 1 |
| Methyl Parahydroxybenzoate | 99-76-3 | | 1 |
| Methyl cellulose | 9004-67-5 | Laxatives | 1 |