The most common cause of mucus in the throat is postnasal drip, either from allergic or non-allergic chronic rhinitis, which is inflammation of the nose or from chronic sinusitis, which is inflammation of one or more of the sinuses. However, spitting gross or pure blood is not a feature of rhinitis or sinusitis or of the dry throat you describe although one can see blood-tinged mucus with these conditions.
You should seek a complete examination of your nose and throat by an ENT specialist. There are other causes of such bleeding that you would not want to go undiagnosed.
I found on this website...
Phlegm mixed with some blood could be due to irritation of the nose, sinuses, or lungs. Swallowing this blood will cause it to end up in your stool.
On the other hand if you are coughing up blood and not blood-streaked phlegm, you should be seen on an emergency basis. For blood to be found in the stool, it must either originate in your digestive tract, or be swallowed in large quantities from another source. You will need to be seen by a doctor without delay in order for the source of the bleeding to be found and treated. If the bleeding is severe this could be life threatening
I hope this helps some! Sorry im not too much help
mostly thats saying about blood being in the stool but it also states that the blood probably is coming from an irratation of some sort.