Tropane alkaloids are a class of alkaloids and secondary metabolites that contain a tropane ring in their chemical structure (see the picture to the right). Tropane alkaloids occur naturally in many members of the plant family Solanaceae.
- Atropine, racemic hyoscyamine, from the deadly nightshade (Atropa belladonna)
- Hyoscyamine, the levo-isomer of atropine, from henbane (Hyoscamus niger) and mandrake (Mandragora officinalis)
- Scopolamine, from henbane and Datura species (Jimson weed)
All three acetylcholine-inhibiting chemicals can be found in the leaves, stems, and flowers in varying, unknown amounts in the tree-cousin of Datura, (Brugmansiae) more commonly known as Angel Trumpets or Devil's Weed.
Stimulants and cocaine-related alkaloids:
- Cocaine, from Erythroxylum coca
- Ecgonine, a precursor and metabolite of cocaine
- Benzoylecgonine, a metabolite of cocaine
- Hydroxytropacocaine, from Erythroxylum coca
- Methylecgonine cinnamate, from Erythroxylum coca
Non-natural tropanes 
There exist some synthetic analogs of tropane alkaloids, see
They are not considered to be alkaloids per definition.