Dear Panthera,
Thankyou for your detailed and prompt reply - I appreciate your view-point. Do not worry, I can assure you that I would NOT attempt this case myself, as I am well aware of my inexperience and limitations. Unfortunately when my friend asked me for advice, I did not have either the expertise or knowledge to advise her. Hence, my posting to BB. I shall take your advise and try to encourage her to refrain from her habit, at least until breastfeeding is over. I agree with your 3rd point...and 'reasonable health' was her vague description of her child. They live in Scotland, so I can not verify this first-hand as contact is limited. I have managed to source 2 classical homeopaths locally to her, and I shall pass on details.

Dear Kkrista, thankyou also for your comments. Do not worry either, I am actually quite liberal minded and diplomatic.......I will not be 'jumping down her throat'. I am concerned for her families welfare, and I am responding to her conscience and her fear of long-term health consequences in her children. I appreciate cultural differences in attitudes to cannabis - however her use is FAR from recreational. The sheer amount of stuff she is smoking alarmed me most. I have already done a google search a few days ago - but it is surprising how little information and research there is on this topic. I did come across a document suggesting a link between maternal cannabis smoking and childhood leukemia. (It would be interesting to know if there was a higher incidence of leukemia in countries were mothers smoking cannabis was more common).