The invention provides methods of thickening aqueous compositions without increasing stringiness. The method involves using, as thickeners, polymers of polyacrylic acid, poly(2-acryamide-2-methylpropanesulfonate), or salts thereof, having a weight average molecular weight of 500,000-8,000,000. The polymers contain no more than 10 mass % of polymers having a molecular weight of 10,000,00 or more, and/or contain no more than 10 mass % of polymers having more than three times the weight average molecular weight. Aqueous solutions of these polymers have a low degree of stringiness, and are particularly useful as thickeners for cosmetics.