The solubility of paracetamol (4-hydroxyacetanilide) in binary mixtures of acetone + water and acetone + toluene and in ternary mixtures of water + acetone + toluene is reported. The temperature range is -5 to +30 degrees C. In acetone + water the solubility increases to a maximum at approximately 25 mass % water before decreasing to a much lower value in pure water as compared to pure acetone. In acetone + toluene the solubility decreases monotonically with increasing toluene concentration. The water content has a strong influence also in ternary mixtures. Activity coefficients in the saturated solutions are estimated.