What does it mean when your stool has a little blood in it when it's hard and none when stool is in diarrhea form?

Maybe straining but: ...blood in stool is a warning sign. Brisk bleeding warrants emergency care. Causes of bleeding may be predictable (e.g. rectal trauma), but evaluation is always appropriate. A rule of thumb (but not absolute): black stool means bleeding comes from upper GI tract; grape jelly stool from small bowel; silver stool from biliary tree; burgundy stool from right colon; red blood from left colon to anus.