The negative energy of an envious person can cause physical symptoms that are not related to a disease, such as weakness, eye infections, upset stomach, fever and nausea. Also, it is likely that the affected person will have personal, family or professional problems without any apparent cause. This method is practiced in Eastern Europe. Simply drop a piece of charcoal into a pan of water. You can also use the head of a match that has burned. Sinking is a good sign, while floating means a person or child has been affected. Usually a parent or healer performs these rituals, if the sufferer is a child. If not, the sufferer can perform them. Another method is to drip hot wax into holy water. Watch how the wax reacts. If it splatters, it means you or the child you are testing for have the evil eye. The same is true if it sticks to the side. People in the Ukraine employ this method. With this method, the person diagnosing the condition drops oil into water. If it forms an eye, the child is thought to have the evil eye. Another way is to pour oil over a lock of the affected person's hair into a glass of water (preferably holy water). If the oil sinks, then the person has the evil eye.  In turn, special prayers are said until the oil doesn't form an eye to cure it. The person dropping the oil is praying for the evil eye to leave the person. Some suggest there are special prayers for this process, which you can learn from a local healer.

===
Write a summary of the previous text in Vietnamese:
Chú ý các triệu chứng. Phương pháp sử dụng than. Phương pháp dùng sáp. Phương pháp dùng dầu.