This theory of human motivation cannot rule out altruism without being contradicted by evidence. Rather, it claims that when sane people choose to help others, it is because of the pleasure they themselves obtain, directly or indirectly, from doing so.
Psychological hedonism is quite an extreme proposition, and there are a number of thought experiments and psychological studies which appear to make it untenable.
Pyschological hedonism is a special case of psychological egoism, in which the concept of "self interest" is equated with pleasure.
See also: hedonism