The cholesterol-lowering effects of plant sterols in a format suitable for use in China have not previously been investigated. We conducted the study to quantify in adult Chinese the effects on blood lipid concentrations of a plant sterol-enriched milk tea powder. The study was a double-blind, randomised trial in which 309 participants were randomised to receive daily 2·3 or 1·5 g plant sterol supplementation or placebo for 5 weeks. The milk tea was consumed with the two fattiest meals of the day with half the assigned daily dose taken on each occasion. Fasting venous blood samples were collected before commencement and upon completion of randomised treatment. The mean age of study participants was 44 years, 62 % were female and 62 % had a history of hypercholesterolaemia. Baseline mean total cholesterol was 5·5 mmol/l and LDL-cholesterol was 3·2 mmol/l. Compared with placebo, the 2·3 g/d plant sterol dose reduced total cholesterol by 0·25 (95 % CI 0·07, 0·43) mmol/l (P = 0·01) and the 1·5 g/d dose by 0·23 (95 % CI 0·06, 0·41) mmol/l (P = 0·01). For LDL-cholesterol the corresponding reductions were 0·17 (95 % CI 0·00, 0·35) mmol/l (P = 0·06) and 0·15 (95 % CI − 0·02, 0·32) mmol/l (P = 0·08). For neither outcome was there evidence of differences between the effects of the two doses (both P values >0·4). In conclusion, the consumption of plant sterol-enriched milk tea decreased cholesterol concentrations although to a lesser extent than was anticipated. The reason for reduced efficacy is unclear but may be attributable to the novel food format used or the Chinese population studied.