New story! I wanted to finish this before I started posting but now I'm thinking having it posted may motivate me to finish more quickly.
This story is written for LFB72 and is based off of a prompt by her. Please enjoy!

Merlin returned from serving Arthur's dinner to find Gaius chopping something, a small pot boiling over the fire. Sitting across from his mentor, he saw it was autumn crocus leaves being minced into fine pieces. Autumn crocus is poisonous, but small amounts of it make for an effective gout treatment. Merlin couldn't imagine what he would need this much for.

"What's all this?"

"Wild garlic for tonight's stew." Gaius swept the greens off the table and started making his way to the cauldron in the hearth.

"Wait!" Merlin sprang in front, pushing Gaius back toward the workbench. "That's not wild garlic, Gaius..." The leaves were similar, but Gaius was well aware of the differences. "Smell it."

The physician sniffed at his hands, brow wrinkling in confusion when he failed to sense the telltale odor of garlic.

Merlin spotted the remains of arnica and nettles in a bucket and guessed at what had happened.

"Gaius, did you make some of your gout tonic today?"

The elder frowned, still staring at his hands as he sank onto a stool. "I... I don't remember. I intended to?"

Merlin didn't like that uncertainty. He emptied the basin into the waste bucket as Gaius washed the green from his hands.

"Ehm... just... sit, yeah? You must be tired; I'll take care of dinner."

Gaius nodded, still clearly upset by what had happened - of course, Merlin was too. If they'd eaten those leaves there would have been no antidote for the toxins. He'd seen someone die after ingesting autumn crocus; it was not something he wanted to experience ever again. Even the arnica could be poisonous if that had also found its way into the "stew". Either way, he couldn't take a chance.

"I'll be right back." He used a hook to remove the pot and carry it to the privy, carefully disposing of the contents. A trip to the outside pump and the pot was ready to contain something more edible, but it was too late to be putting a stew on now. Instead he swung by the kitchens and made up a plate for Gaius, claiming the king had demanded seconds. He wouldn't get a full meal for himself this way, but he pocketed a piece of bread that would be enough when combined with an apple Arthur had thrown at him earlier.

When he opened the infirmary door Gaius was rifling through the cabinets, muttering to himself.

"What are you looking for?"

The old man startled, knocking a candle onto the floor. A frantic wave of Merlin's hand extinguished it before any harm was done.

"Merlin!" Gaius admonished out of habit, then glowered at the pot in his ward's hand. "What were you doing with the pot? I need that to make dinner!"

Icy fear spread through Merlin's veins and froze him in the doorway.

"Well don't just stand there – give me that pot!"

"I- I brought you some food from the kitchens." He slowly walked to the table and set down the plate, not sure how to react.

"Oh, well... thank you." Gaius looked stunned, sitting and happily tucking into the fine food. "Aren't you going to eat?"

"I, um, ate earlier." He squirmed under his guardian's stare. "Goodnight, Gaius."

He fled to his room, stomach too unsettled for the bread and apple.

A night of scouring his spellbook had revealed no likely magical cause for Gaius' behavior, but that didn't stop him from casting a few cleansing and healing spells over the sleeping man in the early morning hours.

He didn't want to admit it, but this probably wasn't just a temporary affliction brought on by some curse or hex. Gaius had always had the occasional incident of forgotten words or misplaced items, but Merlin had put that down to old age. Lately, however, they were getting more frequent and more serious. What if that had been a patient's medicine he'd mixed up? Merlin shuddered and wrote a note informing Gaius he would take care of the rounds – he'd need to double check everything the physician had done the previous day.

He avoided thinking about what he'd do tomorrow and the day after that.

The gurgling of his stomach reminded him that time was ticking on and he shoved last night's bread – now hard – into his mouth as he filled a basket with the tonics for Gaius' regular patients. He'd have to come back to collect any additional medicines while Arthur ate breakfast.

Casting one last worried glance at his surrogate father, Merlin left to begin the day.