Crumpton (40), a Dunedin nurse, won the 42km race by a massive seven minutes and also broke the record for the Auckland event by a minute with her time of 2hr 45min 46sec.
The old record was held by Aby Ngawati (Whangarei), who ran 2hr 46min 47sec when winning the event two years ago.
She was second yesterday in 2hr 52min, just ahead of third-placed Vicky Jackson (Wellington).
"I've run 20 marathons but this was the first time I've had diarrhoea in a race," Crumpton said.
"It was stressful because I didn't know where the toilets were on the course."
Crumpton had toilet stops after 18km, 25km and 30km. The first thing she wanted at the finish was a toilet.
"I had to rush there before I could talk to reporters at the finish," she said.
Crumpton took the lead after 1km and was never in danger of being caught after that.
"It was an uncomfortable race with my stomach rumbling all the time," she said.
It was a profitable day for Crumpton, who collected $500 for being first to the top of the Auckland Harbour Bridge after 15km in the race, which started at Devonport. She also collected the winner's purse of $3000.
It was Crumpton's third marathon title after winning in Christchurch in 2005 and Invercargill last year.
Crumpton now has 12 New Zealand senior women's titles, and four records in major events.
It was Crumpton's fourth marathon this year. She was fifth on the Gold Coast and won in Noumea and in the Lydiard Legends event in Auckland.
Her next target is the 60km Kepler Challenge in December, an event she will be taking part in for the first time.
Crumpton is coached by Wellington-based Kevin Ross, as is Dunedin's Kim Herbert-Losier, who ran a personal best 3hr 16min.
