| Lycopodium | |
| Lysergol | 602-85-7 |
| Lysozyme | 54-21-7 |
| Macitentan intermediates | 147962-41-2 |
| Macrogol 15 hydroxystearate | |
| Macrogol 20 glycerolmonostearat | |
| Macrogol 600 | |
| Macrogol Cetostearyl Ether 20 | 9004-98-2 |
| Macrogol Stearate 8 | |
| Macrogol stearate 20 | |
| Magaldrate Powder | 74978-16-8 |
| Magnesium DL-Aspartate Tetrahydrate | 2068-80-6 |
| Magnesium Monoethyl Fumarate | 83918-60-9 |
| Magnesium bromide hexahydrate | 13446-53-2 |
| Magnesium fluoride | 16674-78-5 |
| Magnesium salicylate | 18917-89-0 |
| Malathion | 121-75-5 |
| Maltose | 69-79-4 |
| Manganese carbonate | 598-62-9 |
| Manna | |
| Marian thistle | |
| Maribavir | 1599432-33-6 |
| Marigold flower | |
| Mate leaf | |
| Matricaria | |
| Matuzumab | 339186-68-4 |
| Maxacalcitol | 103909-75-7 |
| Maytansinol | 57103-68-1 |
| Meadowsweet herb | |
| Mebhydrolin Napadisylate | |
| Mecamylamine | 60-40-2 |
| Mecasermin | 68562-41-4 |
| Mechlorethamine | 51-75-2 |
| Medetomidine hydrochloride | 86347-15-1 |
| Meglumine | 6284-40-8 |
| Meldonium | 86426-17-7 |
| Meldrum's Acid | 2033-24-1 |
| Melengestrol Acetate | 2919-66-6 |
| Melitracen Hydrochloride | 10563-70-9 |
| Melperone | 3575-80-2 |