First, read the English article below.

Dehydration can aggravate the symptoms of rhinitis and postnasal drip. Avoid caffeine and alcohol, which can cause dehydration. Water is the best choice to remain hydrated while suffering from rhinitis and postnasal drip.  Look at your urine to determine if you're getting enough water during the day. If your urine is yellow, you're probably not getting enough water. If your urine is clearer, with at most a hint of yellow, you're probably drinking enough water. Drinking warm fluids, such as water, is especially helpful for relieving postnasal drip. Blowing the nose can remove irritants, which causes a buildup of mucus. For mucus that cannot be cleared after blowing the nose, some people prefer snorting and spitting the excess mucus from the back of the throat, avoiding bad breath and dry mouth. Over the counter saline kits and nasal sprays are available to rinse the nasal cavity. The saline solution flushes the irritants from the nasal cavity, thins the mucus and relieves the membranes in the nose.  Try using a Neti pot to clear out the mucus in the sinus and the back of the throat. Be aware, however, that by using a sinus irrigation device you could be removing natural antimicrobial agents that get rid of enemy bacteria, viruses, and fungi. Apply 2 to 3 saline nasal drops every 2 to 3 hours to help moisten your nasal passages and relieve congestion. Try using Nasya oil 2 times daily as a way to relieve postnasal drip. Oral decongestants narrow the blood vessels to reduce the amount of congestion in the nasal cavity. Decongestants are also available in a nasal spray. If symptoms don't get better after 3 days, discontinue use of decongestants. Use of decongestants after 3 days may be more harmful than helpful because it may lead to rebound congestion. Medications such as guaifenesin (Mucinex) are sold OTC and taken in tablet or syrup form. These help to thin out the mucus and make it easier for it to run out. Follow the manufacturer’s instructions for how to take this medications, and ask your doctor or... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Uống nhiều chất lỏng để bù nước. Xì mũi thường xuyên để tống dịch mũi dư thừa ra khỏi khoang mũi. Rửa mũi để loại bỏ chất kích ứng gây tiết dịch mũi. Dùng thuốc giảm nghẹt mũi bán tự do tại hiệu thuốc để giảm nhẹ triệu chứng tích tụ dịch mũi thừa và chảy dịch mũi sau. Chỉ dùng thuốc giảm nghẹt mũi trong 3 ngày liên tiếp. Loại bỏ dịch mũi bằng thuốc làm loãng dịch mũi. Tham khảo ý kiến của bác sĩ đối với loại thuốc cần kê đơn để giảm kích ứng và tích tụ dịch mũi.