Homepathy also works on a "like cures like" basis - the remedies given to counteract symptoms are potentisations of substances that would cause those same symptoms if given in large amounts. These small doses don't attempt to efect a cure themsleves, but sort of kick start the body into getting itself into balance.
Homeopathy is also a more holistic therapy - it tries to make people well, not cure illness. A homeopath will therefore look at all aspects of a persons life before prescribing, wheras herbal medicine is more focused towards providing a herbal remedy to solve a problem, in much teh same way that a conventional doctor might prescribe a prescription drug to cure a problem.