Is it normal for elderly to forget that they have had a bowel movement?

yes it is normal .
im only 47 and i dont even know if i had one today or not ...

we have been marking the calendar showing the date/time of bw to remind her and it seems not to register that she one. Daily routine is "mom" I haven't gone in 3 months or 2 weeks and try to tell her and at times she gets angry and start calling us liars. Is it best just to ignore her and walk away or is there something else we can do?

Buy candy that look like pills--give her one with a glass of water-tell her it will help her bm problem--

I'll second that lhardebeck..I'm 62 and don't remember either.
My problem with my father is not if.....but where!

g1917 ...this has been one of my biggest problems! Exactly what you said is what I have been living! I have had to spend my birthday at the er , with my alzhemiers momz for no reason. Because of a "I havent had a movementin 3 months " episode. The er doc took all types of unnessary tests...and told her she is fine. Still I go through this with her.
My momz called me a liar...she got my uncle into it ( long distance phone call- screamin match) and he told me to take her to the er...that would stop it. I did, it hasnt stopped.
She is continually doing a circle of laxatives/anti diahreeh over the counter meds, people tell me dont buy them...but if i dont i suffer worse nagging and verbal abuse.... Thats part of the reason why I have to get her placed...she wont listen to me ...and is ruining her system.
The doctors tell me this is common. So in a nursing home they will handle these things.
I am sorry...I said this to tell you...yes it is normal.

Buy flax seeds, grind about 1 Tbsp, to begin with, in a coffee or spice grinder, or in a small mason jar if your blender will allow that. Mix the meal with flavored yogurt, pudding, sprinkle on seasoned food, in peanut butter -- anything. There will be a soft bm the next day. If necessary, increased the amt of seeds you grind...maybe slowly work up to 4 Tbsp, depending on how sluggish the bowel.
The seeds must be ground to allow the body to use the Omega
fatty acids in the seeds. The meal is a bit dry & is flavorless.
It is healthy and it 'works' great. I have even made a variety of
muffins and mixed in a tsp of flaxseed meal into each bit of batter in the muffin tin cups. Flaxseed meal (ground seeds) can
also be purchased. Keep refrigerated. Use within abt 2 months.

It is very common that they forget and become obssesed with their BM. Since the elderly are prone to sluggish bowels and dehydration, a leading cause of sluggish bowels, it is very important that you track when she did have a bm to prevent an impaction that can lead to an unnecessary hospitalization. the lax/imodium rollercoaster is a bad choice. I usually have my patients on a colon cocktail with one meal a day, most often breakfast. It consists of 1/3 cup of bran flakes, 1/3 cup of apple sauce and 1/3 cup of COLD prune juice, mixed together. It takes 4 or 5 days to kick in so if they are constipated it is slow to help. Once they are on it it gives them a natural regularity. And it is way less expensive than the lax/imodium ride.

It's normal to forget- for some people it may the biggest part of their day and for others it doesn't regester. As we age, there will come a time when day's melds with another. There is no "normal" regularity- each person is unique. Some people go daily or twice daily and others go every other day or third day etc.

Mom is prone to constipation and has been hospitilized a number of times in the past dur to this condition. We finally unhooked the lever to flush the toilet and hooked up a monofilament fishing line in back that she can't see. I flush the toilet, not her. I can now keep an accurate record of her movements and know when to give Miralax (at the physicians direction)

Should all relatives, and friends be aware of the fact that a relative memory problems? A doctor said little support will come once people know that there is a problem.