Pipettes working with an air-cushion principle are most commonly used in labs around the world and highly accurate for most pipetting applications. However, the precision and repeatability of the pipetting results can be affected when working with liquids of different viscosity, volatility, surface tension or density than water. In these cases, and also when the liquids are foaming, positive displacement pipettes simplify the pipetting process and secure accurate results. In addition, positive displacement pipettes eliminate the risk of cross-contamination and protect the end user and the instrument from hazardous liquids. Read in the following how to cope with these liquids, even if you should only have an air-cushion pipette at hand.