my one month old had a string of blood only once in his poop. and it was also mucusy. two times this morning he pooped, and it was like literally a yellow greenish ball, like play doe. it wasnt soft, it was firm. then later on in the day she pooped normally, liquidy. then he pooped with a little string of blood and some mucus. she just pooped about an hour ago and it was just a little bit, but it was his normal poop, yellow and liquidy. He is only formula fed..and He is always really really gassy..sorry if there is alot of info.