Orthosiphon staminaeus is a herbaceous plant (up to 1.5m h) bearing campanulate whitish-bluish flowers with long exerted filaments (giving its namesake "cat's whiskers"). The leaves are in opposite pairs with lanceolate blade and serrate margin. It is grown both for its medicinal and aesthetic values.

Two main ethnic use of this plant are for its diuretic and anti hypertensive effects. Several studies have given some insights into these traditional claims. The lyophilized extract enhanced ion excretion in rats1, and in a clinical trial in Thailand, the extract was shown to increase citrate and oxalate excretion in man suggesting a potential use in reducing kidney stones.2 Methylripariochromene A isolated from O. staminaeus were shown to decrease systolic blood pressure and increase the excretion of Na+, K+, and Cl- in rats.3

References:

1. Doan DD, Nguyen NH, Doan HK, et al. Studies on the Individual and Combined Diuretic Effects of Four Vietnamese Traditional Herbal Remedied (Zea mays, Imperata cylindrical, Plantago major and Orthosiphon stamineus). J Ethnophamacol. 1992;36(3):225-31.
2. Nirnoy M, Muangman V. Effect of Folia Orthosiphonis on Urinary Stone Promoters and Inhibitors. J Med Assoc Thai. 1991;74(6):318-21.
3. Matsubara T, Bohgaki T, Watarai M, Suzuki H, Ohashi, Shibuya H. Anti hypertensive actions of Methylripario Chromene A from Orthosiphon aristatus, an Indonesian Traditional Medicinal Plant. Biol Pharm Bull. 1999;22(10):1083-8.