In all organisms from bacteria to humans, specific hydrolases--pyrophosphatases--hydrolyse inorganic pyrophosphate to phosphate. Without this, DNA, RNA and protein synthesis stops. Pyrophosphatases are thus essential for all life. In humans, disorders in pyrophosphate metabolism cause chondrocalcinosis and hypophosphatasia. Currently, pyrophosphate analogues, e.g. alendronate, are in clinical use in osteoporosis and Paget's disease but also for e.g. complications of prostate cancer. In bacteria and protozoan parasites, membrane-bound pyrophosphatases (mPPases), which do not occur in humans, convert pyrophosphate to a proton or sodium gradient. mPPases, which are crucial for protozoan parasites, are thus promising drug targets e.g. for malaria and leishmaniasis.