★★★★★
The symptoms you might experience are a wooziness and drowsiness when you take too much turpentine because turpentine also has a sedative effect. Turpentine also can have a laxative effect, but I have only ever experienced a slight loosening of the stools when I took 2 tspns of turpentine in one go(double the normal dose). And if there is any ongoing disease in the blood or bowels, such as Hepatitis C, then you may well get a Herx or die-off reaction as well.
You can also take turpentine baths if you wish. Add one or two small shot glasses of turpentine into the bath and stay in the bath for about 1/2 hour. The iso-penenes in turpentine, the main beneficial ingredients, are also easily absorbed through the skin.
For interests sake, and to allay any fears, medical doctors commonly used and recommended internal teaspoon dosages of turpentine in the past.
Here are some examples of older turpentine usage and dosages:
The Physiomedical Dispensatory 1869 - Turpentine Usage