It's not exactly cruel, but it's also not exactly the most pleasant way to die. We recently pulled a patient's feeding tube (in accordance with her own wishes -

It's not exactly cruel, but it's also not exactly the most pleasant way to die. We recently pulled a patient's feeding tube (in accordance with her own wishes - she had terminal cancer, and had been able to see the end coming for a while), and it took her a full freaking eighteen days to die on no sustenance but a single cup of water someone gave her on day six. We obviously had the poor woman on a morphine pump the whole time, so she was too out of it most of the time to suffer much, but it's not a perfect system - she kept having moments where she'd become more awake and agitated, and I did feel like she was experiencing some suffering in those moments during our best efforts. Coincidentally at the same time, I had to have my cat put to sleep. The vet came to my house, he received a single injection, and then he peacefully fell asleep in my arms without so much as a twitch. The entire process took not five minutes altogether. I know which way of dying I'd prefer, if it was my terminally ill body at stake.