Don't mess with Granny.

A restaurant owner in San Francisco trusted her gut and flew to defend her business — and family — when a disgruntled customer got rowdy, and threw a jug of hand sanitizer in the direction of her young grandson.

On Friday night, the anonymous customer got upset when her order wasn’t yet ready for pickup from Panchita’s in the Mission District, NBC Bay Area reports.

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Manager Doris Vargas said that the customer began cursing from across the counter, just as her 2-year-old son got dropped off at the restaurant and wandered over to be with her, per KTVU FOX 2.

“She was just throwing profanity at me and at that point my son was getting dropped off," Vargus explained. "He naturally climbed onto me."

Vargas' mother Doris Campos, who owns the restaurant, came out of the kitchen to see what the fuss was about. Trying to intervene, Campos claimed that the woman said she wanted to “kill” her daughter and remained irate.

As surveillance footage shows, the patron then got violent, chucking a 5-pound bottle of hand sanitizer towards Vargas, who was holding her toddler.

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“I’m thinking, if it hit my grandson, I mean, I do whatever I have to do,” Campos said. “That’s all. I wasn’t thinking at that moment.”

Campos sprang into action, throwing a bag of food at the disgruntled customer and pushing the counter (which was a table) towards her. The customer knocked it over, while another employee tried to pull the woman away.

Doubling down on defense, Campos flipped the table onto its side and used it as a barrier to push the customer out the door of the restaurant.

The woman fell over, and a passerby ran in to see what was going on.

FOX 2 reports that Campos called the police, but the angry customer ran away before law enforcement arrived. No one was hurt during the encounter, but a big dent in the bottle of hand sanitizer serves as a reminder of the harm that could have been done.

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The mother-daughter duo now hope to have the woman identified and held accountable for her actions.

"Small businesses are struggling a lot during the pandemic and to have customers act this way is really unacceptable," Vargas said.