Large language models (LLMs) like GPT-4, Llama, and Bard are prone to hallucinations, which occur when they generate nonsensical or unfaithful responses. This can happen due to limited knowledge in their training datasets, lack of factual accuracy checks, and optimization for generating probable responses rather than true ones. Hallucinations can be influenced by prompt engineering, where the LLM is convinced to mimic a specific persona or respond in a certain way. Vectara's Grounded Generation approach addresses this issue by augmenting the LLM's knowledge with external sources, providing more accurate responses and increasing trust from users, allowing for safer deployment of LLM technology across various use cases.