Question 971465
Without being able to draw such a diagram, it is very difficult to convey what it does.  A Venn Diagram would have circles for each individual side effect, and what was outside all the circles would be no side effects.  

Sore throat and thirst would intersect in part.  They occur together twice, but 5 other times, sore throat is alone and 4 times thirst is alone.

When you have three, they represent the small area where three circles intersect.

nervousness and nausea intersect    7 times
nervousness and dizziness intersect  3 times
nausea and dizziness intersect without nervousness 3 times
All three intersect.  1 time
There are places that they occur without the others.  

The Venn Diagram shows the relationships by means of circles intersecting, whereas to find the same in a table listed above is more difficult.