A Perth woman has been accused of trying to murder her husband of 39 years after he suspected her of slowly poisoning him.

The 62-year-old suffered from mystery illnesses such as gastritis and hair loss for over a year before he started to suspect his wife was poisoning him.

In a covert operation, the man set up a secret camera which revealed his wife had been spiking his drink bottles with saline medication.

WAToday court reporter Heather McNeil told Oliver Peterson on Perth Live this is one of the most bizarre cases ever.