M – M
| Majorana hortensis | Marjoram |
| Malva vulgaris | Common mallow |
| Marrubium album (M. vulgare) | Horehound |
| Marrubium peregrinum (M. nigrum) | Black Horehound |
| Matricaria chamomilla | Chamomile |
| Melilotus officinalis | Sweet clover |
| Melissa officinalis | Lemon balm |
| Melittis grandiflora (M. melissophyllum) | Bastard balm |
| Mentha aquatica | Water mint |
| Mentha crispata | Wrinkled-leaf mint |
| Mentha piperita | Peppermint |
| Mentha pulegium | Pennyroyal |
| Menyanthes trifoliata | Bogbean |
| Mercurialis annua | Annual mercury |