REMEDY FOR THE PERSON, NOT THE DISEASE
There is no remedy specifically for a disease type, eg a whooping cough. The remedy is based on the individual, or more specifically the constitution or energetic pattern of the individual. For example, for two people with a cough, one may get better with homeopathic Phosphorus, and the other may use a homeopathic plant remedy, Pulsatilla.
However, in first-aid remedies, you do find remedies for specific symptoms, for the obvious reason that no matter what your constitution, in needing first-aid we are all alike. Eg Arnica is the most widely-used remedy for blunt trauma. (For information regarding the next homeopathic first-aid instruction, email firstname.lastname@example.org).