Grapefruit juice

[1][2] Grapefruit juice is important in medicine because of its interactions with many common drugs including caffeine and medications, which can alter how they behave in the body.

[4] Drugs which are incompatible with grapefruit are typically labeled on the container or package insert.

[5] People taking drugs can ask their health care provider or pharmacist questions about grapefruit/drug interactions.

[8] Canadian regulations on commercially produced and sold grapefruit juice are that it must be made from clean, mature grapefruit and may contain sugar, invert sugar, dextrose, glucose solids and class II preservatives[9] such as benzoic acid, amylase, cellulase and pectinase.

[10] According to Canadian standards, grapefruit juice should contain more than 1.15 milliequivalents of free amino acid per 100 millilitres (3.5 imp fl oz; 3.4 US fl oz); more than 70 milligrams of potassium per 100 ml; and have an absorbance value for total polyphenolics of no less than 0.310.