While blood thinners and aspirin are  generally harmless when taken individually, interactions where one substance  exacerbates the effects of another can also take place between drugs that are independently harmful.
Dok su razrjeđivači krvi i aspirin uglavnom bezopasni kada se uzimaju zasebno, interakcija u kojoj jedna supstanca pogoršava učinke one druge može se odnositi i na droge koje su zasebno opasne.