Cardenolides are a type of steroids. Many plants contain cardenolides in the form of cardenolide glycosides (i.e. cardenolides that contain structural groups derived from sugars; see Glycoside). Cardenolides are toxic (specifically, heart-arresting).
Supposedly, the term derives from Greek kardiā, heart. It shouldn't be confused with cardanolides. Cardanolides are a class of steroids (or aglycones if viewed as cardiac glycoside constituents), and cardenolides are a subtype of this class (see MeSH D codes list).

Cardenolides are C(23)-steroids with methyl groups at C-10 and C-13 and a five-membered lactone at C-17. They are aglycone constituents of cardiac glycosides and must have at least one double bond in the molecule. The class includes cardadienolides and cardatrienolides. Members include:

- digitoxin
- acetyldigitoxins
- digitoxigenin
- digoxin
- acetyldigoxins
- digoxigenin
- medigoxin
- strophanthins
- cymarine
- ouabain
- strophanthidin

Quinapril drug information Cardiac glycoside Pharmacodynamics and clinical effects Thiazide side effects Phytosterols Mechanisms of hypokalemia Indications and usage Inhibitor effects Cardenolides Adverse effects Thiazide Digoxin Warnings Inhibitor adverse effects Clinical pharmacology Ace inhibitor Digoxin clinical use Quinapril faq Precautions Steroid