Their neighbor stinks.

A married Oregon couple is suing their neighbor for more than $200,000 over a foul stench emanating from a tiny mobile home on the property next door that’s so pungent, it caused them to collapse.

John and Trudy Benjamin filed a lawsuit against their neighbor, Karen Ward, alleging that a nasty cocktail of raw sewage and chemicals wafting from her small RV home has turned their Parkrose Heights house of more than 40 years into a toxic nightmare, according to OregonLive.

The couple has even been forced to wear gas masks to withstand the disgusting — and potentially hazardous — aroma, the suit alleges.

Trudy, 67, told the outlet that she began noticing the “life-changing” smell from the rectangular mobile home parked next to Ward’s single-family residence last August and that it steadily became so overpowering that she was unable to enjoy gardening or lounging in her own yard.

“My husband started walking by and started smelling it, and he said, ‘My God, what’s that?’” Trudy told the outlet. “And I said, ‘Yeah, I’ve been smelling it for a while.’”

The couple’s lawyer, Karl Anuta, believes a chemical toilet in the small home may have overflowed and leeched into the ground below it — causing the owners to use bleach to mask the gnarly scent.

However, chlorine bleach mixed with ammonia in urine creates highly toxic chloramine gas, the outlet reported.

The foul stench even caused John, 77, to collapse and chip his kneecap, requiring surgery and extensive physical therapy.

On one occasion, a friend could detect the odor on the couple’s clothes, Trudy alleged.

John and Trudy have been forced to keep their windows and door tightly shut and wear gas masks with carbon filters when they walk out of their car in the driveway, the outlet reported.

Their medical providers advised the older couple to vacate their longtime home and find temporary digs until the stinky situation can be fixed, Anuta told The Post.

“All the Benjamins want is to be able to use and enjoy their home of 40 years, without having to wear industrial-grade respirators whenever they go outside,” the attorney added.

Anuta said the Benjamins sent several emails to Ward after becoming fed up with the smell, but received “unsatisfactory responses,” including that she planned to install a composting toilet, would hook the tiny home up to a sewer line, and have the chemical toilet pumped regularly.

In an email to the local outlet, Ward, who does not have a lawyer, said the tiny home has an “RV toilet” and “portable septic tank” that was installed in the unit. They were both removed in late April, and the residue was cleaned.

The couple, however, said the stench persists, as do the symptoms — dizziness and nausea — that it allegedly causes in them and visitors.

They are seeking “non-economic damages in an amount the jury determines to be fair but in no event to exceed $200,000,” according to a complaint obtained by People.

The Benjamins also want the tiny home removed or no longer used until it’s connected to a sewer system, the outlet said.