Montezuma's revenge sent Vanderpump Rules star Tom Schwartz to the hospital on Monday during a crossover episode with the Bravo show Summer House.

Visiting Summer House's Hamptons crew with his wife Katie Maloney-Schwartz, castmate Stassi Schroeder and her boyfriend Beau Clark, Schwartz discovered that a recent group trip to Mexico had lasting after-effects.

Things started innocently enough.

Crossover episode: Tom Schwartz suffered from Montezuma's revenge Monday during a crossover episode of Vanderpump Rules and Summer House

'In the words of Will Ferrell, we're here to f*** s*** up,' said Stassi, 30, as the gang downed shots at the beginning of the episode.

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But Tom soon shared that he was in a great deal of pain, and had been since their trip.

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'I haven't stopped s***ting,' he said.

'Dude! Two weeks later? That's not right,' said Summer House star Kyle Cooke, 36.

Two weeks: The reality star complained of being sick for two weeks

In a voiceover, he added: 'This is what I love about Tom. He's not going to let a classic case of Montezuma's Revenge ruin his weekend.'

Later in the episode, Tom realized couldn't deny the pain he was in any longer.

'I'm going to the hospital,' he told the housemates.

Good friend: Kyle Cooke praised Tom for partying while being sick

'We're just gonna go and see if he needs to get any kind of…' his wife Katie, 32, trailed off.

'Don't say stitches,' Tom begged.

'It's his butthole,' Katie announced to Stassi, who stood in the hallway, mouth agape as she listened to the couple detail the problem.

Still hurting: Tom complained in bed of pain to his wife Katie

Hours later, the rest of the housemates hit the clubs. They looked at photos of Tom 'in a dress' in the hospital, which Katie sent to them.

'Cheers to Tom's butt!' they said as they drank back at the house afterward.

In a video, Tom said: 'You know one minute you're on the dock, eating a lobster roll, drinking a beer, life's good… and the next minute, you're with your bud at the ER, got a finger in your but, getting a CAT scan.'

Hospital trip: Katie took her husband to the hospital after he complained about being in pain

The verdict: A rectal fissure. The patient was patched up and sent back to the Summer House.

'It's the first time I've ever been double-penetrated,' Tom said slyly.

'What was the second hole?' asked Kyle.

In bed: Tom was diagnosed with a rectal fissure and was patched up before being sent back to the Summer House

'A tube in my arm,' Tom replied.

Previously, Katie, Stassi and Summer House castmate Lindsay Hubbard, 32, drank at a local event and discussed having children.

Stassi said it was 'freaking [her] out' because her longtime pal Katie wanted to have kids now, and 'I thought we would have kids at the same time.'

Reality stars: Stassi Schroeder and her boyfriend Beau came to the Summer House together

'What if you accidentally get preggers?' Lindsay asked.

'I feel like that's the only way I would get pregnant,' said Stassi.

'It's definitely weird talking about children with Stassi and Katie considering when I met them everything was so different,' Lindsay reflected, as old scenes of the women drinking together were shown.

Baby talk: The Vanderpump Rules star talked about having babies at the same time as Katie

Elsewhere during the episode, Kyle talked to Stassi, an old friend, about his plan to propose to girlfriend Amanda Batula, 28, the following weekend.

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Long dogged by cheating rumors, Kyle was visibly upset throughout the show, as he weighed his love for Amanda with her lack of trust in him.

'I feel like I'm an emotional time bomb,' Kyle said. 'I've known I want to propose for months, and then all this f***ing s*** blew my life up.'

Time bomb: Kyle was struggling with his emotions as he wanted to propose to Amanda

'Because the cheating came out,' reasoned Stassi.

'It's the sequence of events that really upsets me because we were talking about me cheating and proposing in the same sentence,' explained Kyle.

'Tough s***—that's what happens when you cheat,' his friend said.

Tough time: Stassi told Kyle that's what happens when you cheat

Kyle and Amanda tearfully made up and headed home.

'This weekend had all of the makings of one of the best of the summer and it's unfortunate because everything just kind of fell apart,' Kyle admitted later.

'But I'm glad I had a chance to talk to Stassi. I value her opinion. She's given me a lot to think about.'

'All it took was one good friend to say maybe you should wait to propose,' he added. 'Maybe I'm rushing things.'

The cast said goodbye.

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'We'll come back next summer with my ass intact,' Tom said.