The homeopathic remedies are prepared in different potencies. 
The Classical approach favours using a “single dose” of the given remedy and using the “minimum potency” (i.e. its strength) to bring about a cure.

In this way the practitioner is able to follow the action of the remedy to establish its curative response. 
If many remedies are used at once it can be difficult to establish which of the remedies has been effective and this is not considered classical homeopathy.