Go to Celadon City and enter the Celadon Mansion. Talk to the old lady on the 1st floor and she'll give you Tea. Then go to any of the thirsty guards, give him the Tea and he and the other guards will let you pass!
To get to Celadon City, go get Flash and go through Rock Tunnel to Lavender Town, then go to the Underground Passage next to Saffron.
Chat with our AI personalities
1. Go to Celadon City 2. Enter the hotel 3. Talk to the old lady on the first floor 4. She will give you tea, and then you give it to one of the guards 5. He/she will say I'll go share this with the other guards, and you can now go into Saffron City any time you want.
got to the mega mart by 5 drinks on the top floor in the machine then go to them and they will talk and then they will have the drink and now you can walk through Edit: Or just talk to the old lady in the Pokemon Mansion in Celdon she will give a hot tea drink.
use the move Flash (TM70)
You have to have an e-reader. the e-reader game is behind them.
There is no blocked gate, just a thirsty guard who won't let you past them and get into Saffron city unless you get them a drink from the Celadon Dept. store from the vending machine. All four guards won't let you past, by the way but the good news is that you only need to buy one drink because they all share the same drink.