doctor's prisciption is better to bring with medicines if medicine is with some heavy doeses, but if you bring regular medicine from India like paracitomal , crowcin , vicks products are not needed any doctor's prisciption, this is not my words, but my cousin is doctor in Canada he is ayurvedic doctor but he moved as dependant of his wife.
even you can purchase these all medicines in Canada over the counter without doctor's prisciption too, even you can buy when you needed. I got some good cold and flu medicines here in the USA better then Indian medicines. even some cough syrups too like Vics nyquil product is nice here in the USA and even available in Canada for cold , cough and flu.
himanshu2277