We Have A 20 Year Old East Indian Guest Staying

We have a 20 year old East Indian guest staying with us on holiday. This morning, she told me she had a bloody nose last night before going to bed, and this morning she has blood in her stool. The air here is very dry compared to where she lives, and I know I have a bloody nose when I go to a drier climate. But the blood in the stool is of concern. She has never had it before. Can it be caused by dehydration?