Sida cordifolia L. (Malvaceae) is distributed along with other species of this genus throughout the tropical and sub-tropical plains of India. Extracts of different parts of the plant are reported to be used in the Ayurvedic system of medicine for a variety of purposes [1]. Ghosh and Dutta previously isolated [2] ephedrine and ψ-ephedrine from the aerial parts of this plant, while Dutta reported [3] the presence of appreciable quantities of H₂O-soluble alkaloids but could not isolate them. Reports on nitrogenous constituents of this family of over 700 species are very few. Gossypium is the only other genus where the presence of two biogenic amines, viz. 5-hydroxytryptamine [4], and histamine [5] has been reported. No true alkaloids have been previously described in the malvaceae. From the roots of this plant, we have now isolated three β-phenethylamines, viz. β-phenethylamine (1), ephedrine (2), and ψ-ephedrine (3), 2 carboxylated tryptamines, S-(+)-Nᵦ-methyltryptophan methyl ester (4) and hypaphorine (5), and three quinazoline alkaloids, vasicinone (6), vasicine (7) and vasicinol (8). In addition, liberal amounts of choline and betaine have been obtained from the H₂O-soluble alkaloid fraction. The stems and leaves contain essentially the same alkaloids as are present in the roots, but in different amounts. Ephedrine and ψ-ephedrine constitute the major bases in the aerial parts, but occur as minor components in the roots. Another interesting quantitative variation has been observed with ageing. The roots of 6-month-old plants afford quinazoline alkaloids as the major alkaloids and only traces of the carboxylated tryptamines. The situation is reversed in roots of 2-year-old plants, which contain carboxylated tryptamines in place of the quinazoline alkaloids. Also, the amount of alkaloids considerably declines in older plants. The occurrence of true alkaloids in a member of the Malvaceae has thus been demonstrated for the first time. The favourable combination of 3 sympathomimetic amines (β-phenethylamine, ephedrine, and ψ-ephedrine) and a potent bronchodilator principle (vasicinone) [6] in this species would account for the major therapeutic uses of the plant extract in the Ayurvedic system of medicine.