i dont want to come off bashing your mother in law but.....
ok, i've never heard of not taking it if you cramps or what not. if you have the squirts, yes, then you may want to lay off of it cos in high doses it can cause that. if you have cramps, chances are you are eating something you should not, like milk/dairy since most of us with CD are lactose intolerant. something is fermenting in your gut causing you to have cramps, unless of course it is the disease itself.
also, chances are you are deficient in omega 3, not 6. most of us nowadays have an imbalance of omega 3 and 6 that shifts toward the 6 (ie too much omega 6 and not enough omega 3). salmon is a good source of omega 3 and 6 fatty acids, but the farm raises stuff, due to its diet on corn pellets and other fish and pcb's, has its omega 3's transformed into omega 6. so get the ocean/wild caught fish to get omega 3 from fish. another good source is grass fed beef (not corn fed). grass fed beef not only has a higher nutritional value than the regular run of the mill stuff, but is leaner and has a higher omega 3 content. also start taking a cod liver oil supplement. not fish oil. not castor oil. cod liver oil. you want it from deep cold water fish. garden of life and carlson labs make good products. you can get them flavored. they dont smell or taste funky. if it werent for the whole D thing i'd drink it like water. vegetables and nuts (specifically walnuts and almonds) and flax seed oil are another source of omega 3 and 6. the problem here is that it is in the form of ALA - the plant based version. your body must first process it into usable forms (EPA and DHA if i am not mistaken here) and then your body can use it. so although these are good ways to get your omega 3 and 6, animal based forms are preferred.
if you question anything i have said, do the research and you'll see that i have not led you astray (also i just gave you the skinny cos i didnt want to type a book). family and friends always want to help us, but it is always good to take things with a grain of salt and check up on it first. so i am glad you came here and asked this question.
best of luck!
Crohn's since 1993 (17 yrs old then)
been on basically every med available, currently on colozal & 6-mp
surgery in July '05 - removal of 2 inches at ileum and 8 inches of sigmoid colon (had fistula into bladder)
Nov '05 developed colonic inertia; July '06 told i needed ostomy surgery
began maker's diet in August '06 - now feeling the best ever with no symptoms of colonic inertia and i kept my colon