There are substances to which our body reacts adversely, this causes an allergic reaction. Almost everyone is allergic to something or another. Some people are allergic to peas, some to bee pollen and many are allergic to specific medications.
The same is true with herbal supplements too. Not all supplements will suit everyone; some supplements may cause allergic reaction. This also holds for Garcinia Cambogia extract. If you read online reviews of users of this extract you will come to know that a few people felt nauseated other developed headaches etc. after taking GCE.
Fortunately, number of people who seem allergic to Garcinia Cambogia extract is very small and the allergic reactions too are not very serious in nature and easily subside.
If you develop allergies easily, the best way to find if Garcinia Cambogia extract will suit you or not is by consulting a doctor about it and explaining your allergic history. Another way is to try a few small / minimum dosage of extract and see how your body reacts. If you feel your body is reacting negatively stop taking the extract and visit a doctor.
Allergic reaction seldom happen if the extract is pure and genuine. Thus, take extra precaution while buying Garcinia Cambogia. Spurious extracts have higher probability that they will cause harm to your body.