Hello Welcome in H.C.M. Regarding your query for constant cough and cold to your 3+ years old child, though you are giving him ayurvedic medicines for increasing immunity. Considering all aspect of medical history, suspition of asthma in your child by your family doctor I would like to tell you that asthma is an allergic disorder and it has got familial history as well. My suggesstion is that you should consult a pulmologist and first of all diagnosis should be confirmed by pulmologist after that doctor will tell you about what to do and what not to do for your child to prevent or minimise the episodes. Probably above answers your query. Regards.