Do I need ETH for Uniswap?

Excuse me, I've been hearing a lot about Uniswap and its role in the crypto world. But I'm still a bit confused about something. Do I actually need ETH for Uniswap? I've read that Uniswap is a decentralized exchange, and I understand it uses smart contracts on the Ethereum blockchain. But does that mean I have to have ETH in my wallet to use it? Or is there a way around it? I'm just trying to get a clear picture of the requirements before I dive in. Can you help clarify this for me?