If you are concerned about gypsum board dust, you really do not have much to be worried about. Gypsum products are not toxic and will not cause any long-term adverse medical effects. The dust from plaster, however, will potentially irritate the eyes, the skin, and breathing it can result in persistent throat and airway irritation causing cough, phlegm, and difficulty breathing.
As with any type of dust, you do not want to inhale a great deal of it because it can make it difficult to breathe. However, if you do inhale gypsum board dust or if ingested, rinse out your mouth and drink plenty of water. But while negatively affected by it, you will eliminate any of the other associated discomforts by wearing protective eyewear such as safety glasses, and a particle mask while mixing or sanding the product.
You can easily clean up the dust by using a vacuum or by mopping it up off of the floor. If it gets on other surfaces, you can wipe it down with a wet cloth.