I feel that Salima might be innocent. She used to be Bairam Khan's wife and hence he could have brought the argh during one of his wars against other kings. After his death, she might be having sleep worries and hence she might be using the argh as a sleep-inducer. It is dangerous only for pregnant women not for ordinary people. In order to keep it safe, she might have ordered for the dibbi and sent a dasi to bring it to her that night from the dibbi wala. Somebody who might be knowing this might have smuggled some of it and mixed it with the kesar. Remember on knowing about Jodha, she was the first one to go to Jalal and plead for her innocence. But she could not convince him. Fearing that if she revealed the full details, she might be suspected as the criminal might have prevented her from talking any further.The other miscarriages need not have been triggered by the argh. Other means might have been adopted by this so-called criminal. Or else is Salima so mahan that she is doing all this to save Jodha? For some reason which I can't exactly nail down, my suspicions are on Khwaja Shera who might be the real culprit.