From Live Science:
This Week's Question: My daughter heard that grapefruit juice can be toxic for some people. Is that true?
The juice, itself, is not toxic, but you should be careful taking medicine with any grapefruit.
Grapefruit juice can raise the level of some medications in the blood. The effect of grapefruit was discovered after using juice to mask the taste of a medicine. So, be sure to ask your doctor or pharmacist if it is safe to have grapefruit with your medications.
Taking medicine can be hazardous to your health. You have to know what you're doing.
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