Betel quid and areca nut are carcinogenic without tobacco.
Sharma
Dinesh C
DC
D001114:Areca / Q000009:adverse effects*; D002273:Carcinogens; D009059:Mouth Diseases / Q000139:chemically induced; D009062:Mouth Neoplasms / Q000139:chemically induced*; D010947:Plants, Toxic; D014026:Nicotiana / Q000009:adverse effects*
D002273:Carcinogens