My Mother Has Constipation 3 Days Already. She Can Poop

my mother has constipation 3 days already. She can poop but it's just little only because she feels hard to poop all the fecal and she felt pain on her anus. What should I do? this is her first time of having constipation. What medicine should I give to her?

Thank you for your response.

Sincerely,
Ann