We analyzed the composition of cloud droplet residuals and of aerosol particles sampled on a mountaintop site. The data show that about 85 % of the submicron aerosol mass partitions into the cloud phase, and that the uptake of soluble compounds (nitric acid, ammonia, and organic gases) from the gas phase into the cloud droplets is very effective. This will lead to a redistribution of these compounds among the aerosol particles and thereby to a more uniform aerosol after cloud evaporation.