Background Pony #409F
[@Drasvin](/images/90813#comment_332837)
Blood and plasma are used for medicines to give to those who need it as well as for blood transfusion, and often with medicines, the patients' immune systems aren't working as well as they should. If the blood you give has a disease or certain medicines which can mess with detection of those diseases (HIV, HBV, + growth hormones from real people (mad cow)), then it can make their conditions worse and set them back. It's also just a risk for contamination and disease spread. Plasma in particular needs these restrictions because it's used for medicine for those who need plasma medicine, and a lot of those patients have immune system deficiencies.
Blood and plasma are used for medicines to give to those who need it as well as for blood transfusion, and often with medicines, the patients' immune systems aren't working as well as they should. If the blood you give has a disease or certain medicines which can mess with detection of those diseases (HIV, HBV, + growth hormones from real people (mad cow)), then it can make their conditions worse and set them back. It's also just a risk for contamination and disease spread. Plasma in particular needs these restrictions because it's used for medicine for those who need plasma medicine, and a lot of those patients have immune system deficiencies.