Not all juices are equally good. It has been discovered that consuming a lot of grapefruit/apple/orange juice during a medical treatment can obviously reduce the treatment's effectiveness. Earlier, doctors considered juice consumption a welcomed act during a treatment.
You can even notice that some medicine instructions state they are not compatible with the C vitamin. It firstly concerns antibiotics.
The vitamin C contains elements that simply block the penetration of certain medicines inside the blood.
An experiment was carried on: 20 volunteers offered to take antiallergic medicine (MHH fexofenadine) and 10 of them were simultaneously given to drink grapefruit juice and the other 10 water. The medicine showed its 100% effect on the volunteers that drank water, while 9 of the volunteers who drank juice were detected to have been received only 50% of the effect.
So, two advices here: either you read your medicine instructions carefully and see if it's compatible with the C vitamin
or
choose to treat yourself only by juices and fruits. This is even better than taking medicines. It's natural.