This usually only affects the user psychologically but the bad trip may be a result of physical discomfort. Talk to the bad-tripper in a calm manner using straight forward language. Do not leave them on their own Injecting Injecting drugs is a particularly dangerous way of taking substances, if at all possible it should be avoided. At the very least, if you do feel you have to share works make sure they are cleaned properly before someone else uses them. Make sure needles and syringes are clean.
Users can contract tetanus and dangerous infections from dirty syringes and needles.
You can never be sure what you are injecting. You may be injecting anything into your bloodstream which can cause massive damage to your veins and blood circulation system. Join a needle exchange where you can get clean needles and syringes free of charge. It is almost impossible to know how strong the drug is you are taking, or what your tolerance level is after you have stopped taking a drug for a while. It is very easy to overdose when injecting.