I Have A One And Half Year Old Baby Girl.

i have a one and half year old baby girl. she has E. hystolytica (0-2cyst). she has been taking metronidazole for 3 days now. she has very loose poop. everytime she drinks her milk, she poops. so i was worried. so i decided to give her fresh banana to somehow address her loose poop. but now, her poop has many black specks. is it caused by eating bananas? or is it blood?