An alumnus of Uber Eats receives $14 million from a16z to address the mess on WhatsApp for doctors in Latin America

Caroline Merin, a former senior executive at Uber Eats and Rappi, is taking on one of healthcare’s most persistent inefficiencies in Latin America: overwhelming patient communication on WhatsApp. Her startup, Leona Health, has raised $14 million in seed funding to help doctors manage patient messages more efficiently using AI.

The funding round was led by Andreessen Horowitz, with participation from General Catalyst, Accel, Maven Clinic CEO Kate Ryder, Nubank CEO David Vélez, and Rappi CEO Simón Borrero. Alongside the funding announcement, Leona said its platform is now live across 14 Latin American countries, serving doctors in 22 medical specialties.

Merin, who previously served as Uber Eats’ first Latin American general manager and later as COO of Rappi, said her experience in on-demand services highlighted how far healthcare technology lags behind consumer apps. While patients expect rapid responses similar to food delivery platforms, many doctors rely almost entirely on WhatsApp to communicate with patients—often without access to medical records or structured workflows.

“Doctors see patients all day, go home, and then face hundreds of WhatsApp messages they’re expected to answer immediately,” Merin said. “They’re supposed to remember who each patient is without having the health record in front of them.”

Leona Health integrates directly with doctors’ WhatsApp accounts, allowing patients to continue messaging as usual. However, physicians manage all communication through Leona’s mobile app, which prioritizes messages, suggests AI-generated responses, and enables delegation to other team members such as nurses or administrative staff. The platform is also preparing to launch a fully autonomous AI agent to handle appointment scheduling and basic patient intake.

According to Merin, WhatsApp-based communication is a deciding factor for many patients choosing doctors in Latin America. As a result, physicians often feel pressure to stay available nights and weekends, responding to everything from urgent medical issues to administrative requests like school notes or appointment receipts.

Leona addresses this by alerting doctors only to high-priority health concerns while allowing routine or administrative messages to be deprioritized. “The goal is to help doctors regain their time,” Merin said, adding that users report saving two to three hours per day.

While Leona is initially focused on Latin America, the company plans to expand into other regions where WhatsApp-based doctor-patient communication is common and permitted—unlike in the U.S., where interactions are typically routed through electronic medical record systems such as Epic.

Leona Health currently has a team of 13 employees split between Mexico City and Silicon Valley, where Merin says the company is tapping into top AI engineering talent.