There's a Dr Pepper feud in Texas that's leaving many with a bitter taste in their mouth.

Dr Pepper Snapple Group of Plano, Texas, the parent company, is suing a small Dr. Pepper bottling company in Dublin, Texas.

The charge?

The Dublin bottler is violating its licensing deal and infringing on the trademark by selling a sugar cane sweetened version of the popular soft drink, and marketing it as "Dublin Dr Pepper."

The parent company says the bottler is effectively diluting the brand name, by changing it, and is violating its licensing agreement by selling Dr P outside of its six-county territory. The company charges that's hurting the business of other bottlers.

The Dublin bottler counters that it's been selling this version of Dr Pepper since 1891. The Wall Street Journal notes that there are some inconsistencies here:

Dublin Dr Pepper called the company's stance inconsistent, noting Dr Pepper Snapple's corporate website had directed customers to the Dublin bottler's home page and toll-free number as late as this year. The Texas bottler also said the company has not taken similar action against North Carolina and Missouri bottlers that have essentially marketed their products the same way.

But in Central Texas, you don't want to get between someone and their Imperial sugar cane soft drink (no corn fructose, please!).

The Fort Worth Star-Telegram reports that fans of the Dublin Dr Pepper are holding rallies – and set up a Facebook page – to raise money for a legal defense fund.

At a rally July 30, an oversize $25,000 check was handed to a company representative, a pastor read a Bible passage, and "Dublin Dr Pepper" T-shirts were sold.

"It strikes me that today is about the American way," Jeff Kloster said in remarks that he later faxed to the Star-Telegram. "It's about small business. It's about small towns."

The Dublin Dr Pepper rally produced a video, too (see below).

Dr Pepper has deep roots in Texas.

According to the company website, pharmacist Charles Alderton created Dr Pepper in 1885. Alderton worked at Morrison's Old Corner Drug Store in Waco, Texas. The store was owned by Wade Morrison. Legend has it that Mr. Morrison named it "Dr. Pepper" after the father of a young girl he was once in love with.The period was dropped from "Dr." in the 1950s.

The website stays that Dr Pepper is "the oldest major soft drink brand in America."

Given that Dublin started bottling the soft drink just six years after it's invention, it claims to hold the title of "the oldest existing Dr. Pepper bottler."