S. 37(1) : Business expenditure –”freebies” to doctors – sales promotion expenses -The code of conduct prescribed by the Medical Council is applicable only to medical practitioners/ doctors registered with the MCI and does not apply to pharmaceutical companies & the healthcare sector in any manner-Expenditure is held to be allowable -Re assessment with in four years – Change of opinion – Held to be not valid [ S 371(1) , Explanation, .147 , 148 ]