||Parsley is a concentrated, almost caustic, essential oil. It should be used with extreme caution as a single oil. Pregnant women should avoid the use of parsley oil altogether. Parsley is best used as part of an essential oil blend such as LeVallee. While useful for mild urinary tract infections, parsley is contra-indicated for more severe forms of kidney disease and degeneration. Some recent studies indicate the continual overuse of parsley may stress the liver.