Hyperacidity causes sensation of burning inside the stomach, acidic water brash, cutting pain in stomach. Chamomile is relaxant, anti-inflammatory remedy that tones up digestion, provided acidity is caused by eating rich foods and stress. Lemon Balm will be also helpful, if stress is major cause of complain Meadow sweet or Filipendula Ulmaria, though aspirin or say salicylates also reduces acidity, provided a person is not sensitive to aspirin and other derivatives. Lemon juice, coconut juice and harad juice are also beneficial.
For fast remedy, take a piece of gud(jiggery) in your mouth and suck it till burning sensation subsides.