Indole derivatives characterized by having a 1,3,4,9-tetrahydropyrano[3,4-b]indole or 1,3,4,9-tetrahydrothiopyrano[3,4-b]indole nucleus with a hydroxyalkanamine or lower alkoxyalkanamine substituent and a lower alkyl group at position 1 are disclosed. The nucleus is optionally further substituted at position 9 and on the aromatic ring. The derivatives are useful diuretic agents, and methods for their preparation and use are also disclosed.