Esters of cyclohexane polycarboxylic acids are used as plasticisers for polyvinyl chloride to enable products with comparable mechanical properties to be obtained using less polyvinyl chloride. Use of these esters also produces formulations with increased stability to ultra-violet light, improved low temperature properties, lower viscosity and improved processability as well as reduced smoke on burning. The esters of cyclohexane polycarboxylic acids may be used alone or in admixture with other plasticisers when the esters of cyclohexane polycarboxylic acids may act as viscosity depressants. Fast fusing plasticisers may also be included. The formulations are particularly useful in the production of a range of goods from semi-rigid to highly flexible materials and are particularly useful in the production of medical materials such as blood bags and tubing.