My grandmother has a period of time and she suffers from constipation, is there any medication to treat it?

Yes, products can be prescribed/recommended, but not just any products. What is her constipation like? Does she have hard stools, small stools or does she report not going to the bathroom often enough?

Is your grandmother taking any other medications? Does she have any chronic illnesses?

If she is taking other medications, I suggest you contact her pharmacy to validate a safe treatment for her

She could increase her intake of fruits/vegetables and drink more water (if she doesn't have any restrictions) and also move around a bit more if possible

If she needs treatment, PEG powder (Lax-a-day) is often a safe choice for seniors. Check with your pharmacy to see which one is recommended.