NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,894 terms related to cancer and medicine.
Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.
- listen (AL-kuh-loyd)
- A member of a large group of substances found in plants and in some fungi. Alkaloids contain nitrogen and can be made in the laboratory. Nicotine, caffeine, codeine, and vincristine are alkaloids. Some alkaloids, such as vincristine, are used to treat cancer.