There's two ways to handle this, in the meta and in the game. You should do both.
The basic steps here are find out what Alice wants out of the game and why she acts like this and then check with your group that in general this idea meshes with them as a whole. If it does, you're done with the meta. If not, you need to discuss what compromises can happen.
Step 1) Why the Why is important
This is exceedingly important because if you don't know why they are being reckless and impulsive it's very hard to provide scenarios that scratch that itch and still gel with the overall goal. If all you know is she will be impulsive, you have to plan for anything, because she might (read: will) do anything and chances are no matter your prep you'll not expect it.
I play characters like this fairly often and most of the time I do it because I'm naturally ADD and going more than 10 minutes without doing something is hard. Sometimes it's a deliberate character trait but more often it isn't. Another player at my group plays them because he likes the idea of chaos. He's not so much interested in the plot as he is in “what happens if I do this?”
All 3 of these types, the bored ADD, the deliberate impulsive character, and the meta love of chaos, all need different things. The ADD player just needs moments of stimulus every couple of minutes. They don't need anything too big or spotlight stealing, just something to do. The impulsive character design needs ways to show off the character's tragic flaw. The chaos lover needs buttons to push and sandcastles to knock over.
Step 2) Finding out Why
Finding her actual motivation will really help you provide what she's looking for in the game. So pull her to the side and have a frank, honest, but non-judgmental conversation with her. It's absolutely key this does not come off as an attack. The natural instinct is to justify our actions and she may do this, even if the query is presented completely reasonably. I suggest making a list of things she's done that seem incongruous with the tone of the rest of the game, pick one or two, and at some point between games give her a question something like…
"Hey Alice. I've noticed that your character is taking some risky and impulsive actions, like X and Y, fairly often. It seemed a little out of tone with the rest of the game and I wondered if I'm providing you with the experience you're looking for. I don't think there's anything wrong with what you're doing — I want to make that clear — but it's kinda throwing me for a loop. Any chance you can help me figure out the types of things you're looking for so that I can be sure I'm providing them?
Step 3) Adjust the Game to the Why
Spend some time trying to pry into these motivations. Once you're pretty sure you understand them you can start to figure out what you need to add to your game. If that is already jibing with what you have, you're done. If there's some conflict between the two, approach the rest of the group (I prefer to do this individually so people feel free to talk unjudged) and make sure the changes work. If they mention that to Alice, ask if she'd be wiling to have a quick discussion about character choices and theme before the next game. Spend 30 minutes trying to get everyone on the same page. If it takes longer than that you have a more serious problem and might need to do some deep group talks, but it doesn't sound like you are there.
Make the world Real
First and foremost you said she doesn't care about the consequences. That may be, but in a serious game you have to. Actions have results and those results will affect your world. Make sure the things she does don't just disappear into the aether. The people it affects should react like real people. This will possibly (almost certainly) cause trouble for the party. And as such they will care about her actions. And that may get her character to care about her actions. This is great inter-party tension and role play and if you have a mature group you should highly encourage it. The journey her character will have to go through as her actions have negative outcomes on her friends is a classic one and can lead to some really cool places.
Match actions to story beats
Alice's reckless style may not seem to fit because you haven't left room for it. In most serious dramas there are breaks of levity. Sometimes this is done with humor but other times simply with moments of satisfaction where there is no tension. In most serious role playing games, that levity is brought about out of game at the table. Call of Cthulhu games are notorious for being dark and scary in game, with gales of laughter and constant joking happening out of game at the same time. I would suspect the same is true in your game. However even if it's not, this advice will work.
The idea is to try and leave space for humor and levity in-game. Look for story beats that come up when she performs her actions. If you haven't read Hamlet's Hit Points by Robin D. Laws, I highly recommend it. It talks a lot about how story beats work and how to use Up beats (positive moments in the story, where tension is relieved) and Down beats (negative moments where tension is increased). That is what you'll be looking to do: trying to find the right moment to put the ooh shiny in front of her.
If the party has been doing a long, intense scene with a potential enemy/ally trying to convince them of something, stakes are high, and everyone is eager for the outcome... It's the perfect time for her to spot a potion to drink. It will break the tension and lead to some more casual RP. Then ramp it right back up as they try and finish negotiations. However, you can't do this trick too often — and generally never at a climax of a story, only of a scene. You want to use it to break up moments of high drama but not take over the drama. Good rule of thumb: 1 every 4 dramatic scenes.
You should also look to use this to spice up any downtime. I'm a big believer of the rule: if nothing is happening, blow something up. So whenever my party has downtime and they aren't actively pursuing interesting things, I'll make something go wrong they have to deal with. You don't have to do that though: Alice has gift-wrapped you all the trouble you could potentially want. Just point her at the interesting-looking thing and let the chaos happen.
Lastly, if she does something impulsive when you aren't setting it up, try to make it fit the story beats. If things have generally been going well when she does something, now is a great time to have the consequences be a bit more dire. Alternatively after they handle it they immediately find that “bad thing” has happened and they need to prepare for some serious doings ahead. On the flip side, if things have been going bad, this becomes a light hearted incident that the characters themselves should find themselves smiling at. Or, after they are done cleaning up and are furious at the delay, a bit of good news they've been waiting on appears. Try to use it as a catalyst to hit the next story beat. Alice is acting as an embodiment of chaos — in almost any written story that means she will be a symbol of change. While RPGs don't benefit as much from symbolism, if they can follow the same tropes with it they will benefit greatly.