Amelia, 28, and Poonyawat Hirantecha, 40, were arrested at a house in Sai Mai district at about 12.30am.
Police seized 70 grams of crystal methamphetamine, or “ice”, 16 ecstasy pills and a scale.
Police said the couple had confessed that they had bought the drugs from a friend for Bt40,000 for 100 grams and then resold them for Bt800 per gram.
The couple said they had dealt drugs for about a year, police said.
Amelia allegedly was consuming drugs when police raided the house.
She claimed she had used drugs because of stress after a friend invited her to try the substances a year ago, according to police.
She reportedly claimed that she had never personally bought drugs.